2010年2月19日德国重粒子研究中心宣布第112号元素的符号位Cn，它的中文名称为鎶。已知Cn的相对原子质量为277，其质子数是112，则这种原子的核外电子数为（）

A:112 B:165 C:277 D:389

患者男，63岁，全牙列缺失，经口腔修复临床的前期制作，当全口牙列排完后，在架上进行侧方平衡的调整 侧运动时，若工作侧接触，平衡侧不接触，应（）

A:加大横曲线曲度 B:减小横线曲度 C:加大补偿曲线曲度 D:减小补偿曲线曲度 E:加大后牙覆盖

与远中支托比较（）。

A:近中支托减小了基牙所受的扭力，也减小了牙槽嵴的负担 B:近中支托减小了基牙所受的扭力，但增加了牙槽嵴的负担 C:近中支托减小了基牙所受的扭力，不增加牙槽嵴的负担 D:近中支托减小了基牙所受的扭力，但减少了牙槽嵴的负担 E:近中支托减小了基牙所受的扭力，也不能减少了牙槽嵴的负担

The Grand Canyon Standing on the rim of the Grand Canyon(大峡谷), gazing across this giant wound in the Earth’’s surface, a visitor might assume that the canyon had been caused by some ancient convulsion(震动). In fact, the events that produced the canyon, far from being sudden and catastrophic, simply add up to the slow and orderly process of erosion. Many millions of years ago, the Colorado Plateau in the Grand Canyon area contained 1,000 more feet of rock than it does today and was relatively level. The additional material consisted of some 14 layered formations of rock. In the Grand Canyon region these layers were largely worn away over the course of millions of years. Approximately 65 million years ago the plateau s flat surface in the Grand Canyon area bulged upward from internal pressure, geologists refer to this bulging actions upwarding (弯曲上升) ; it was followed by a general elevation of the whole Colorado Plateau, a process that is still going on. As the plateau gradually rose, shallow rivers that winded across it began to run more swiftly and cut more definite courses. One of these rivers , located east of the upward, was the ancestor of the Colorado. Another river system, called the Hualapai, flowing west of the upward, extended itself eastward by cutting back into the upward, it eventually connected with the ancient Colorado and captured its waters. The new river then began to carve out the 277-mile-long trench that eventually became the Grand Canyon. Geologists estimate that this initial cutting action began no earlier than 10 million years ago. Since then, the Canyon forming has been cumulative. To the corrosive force of the river itself have been added other factors. Heat and cold, rain and snow, along with the varying resistance of the rocks, increase the opportunities for erosions. The Canyon walls crumble, the river acquires a cutting tool. Tons of debris, rainfall running off the high plateau creates feeder streams that carreside canyons. Pushing slowly backward into the plateau, the side canyons expose new rocks, and the pattern of erosion continues. According to the passage, how many miles long was the trench that became known as the Grand Canyon?

A:10,100. B:277. C:14. D:10.

The Grand Canyon Standing on the rim of the Grand Canyon(大峡谷), gazing across this giant wound in the Earth’’s surface, a visitor might assume that the canyon had been caused by some ancient convulsion(震动). In fact, the events that produced the canyon, far from being sudden and catastrophic, simply add up to the slow and orderly process of erosion. Many millions of years ago, the Colorado Plateau in the Grand Canyon area contained 1,000 more feet of rock than it does today and was relatively level. The additional material consisted of some 14 layered formations of rock. In the Grand Canyon region these layers were largely worn away over the course of millions of years. Approximately 65 million years ago the plateau s flat surface in the Grand Canyon area bulged upward from internal pressure, geologists refer to this bulging actions upwarding (弯曲上升) ; it was followed by a general elevation of the whole Colorado Plateau, a process that is still going on. As the plateau gradually rose, shallow rivers that winded across it began to run more swiftly and cut more definite courses. One of these rivers , located east of the upward, was the ancestor of the Colorado. Another river system, called the Hualapai, flowing west of the upward, extended itself eastward by cutting back into the upward, it eventually connected with the ancient Colorado and captured its waters. The new river then began to carve out the 277-mile-long trench that eventually became the Grand Canyon. Geologists estimate that this initial cutting action began no earlier than 10 million years ago. Since then, the Canyon forming has been cumulative. To the corrosive force of the river itself have been added other factors. Heat and cold, rain and snow, along with the varying resistance of the rocks, increase the opportunities for erosions. The Canyon walls crumble, the river acquires a cutting tool. Tons of debris, rainfall running off the high plateau creates feeder streams that carreside canyons. Pushing slowly backward into the plateau, the side canyons expose new rocks, and the pattern of erosion continues. According to the passage, how many miles long was the trench that became known as the Grand Canyon?

A:10,100. B:277. C:14. D:10.

The Grand Canyon Standing on the rim of the Grand Canyon(大峡谷), gazing across this giant wound in the Earth’’s surface, a visitor might assume that the canyon had been caused by some ancient convulsion(震动). In fact, the events that produced the canyon, far from being sudden and catastrophic, simply add up to the slow and orderly process of erosion. Many millions of years ago, the Colorado Plateau in the Grand Canyon area contained 1,000 more feet of rock than it does today and was relatively level. The additional material consisted of some 14 layered formations of rock. In the Grand Canyon region these layers were largely worn away over the course of millions of years. Approximately 65 million years ago the plateau s flat surface in the Grand Canyon area bulged upward from internal pressure, geologists refer to this bulging actions upwarding (弯曲上升) ; it was followed by a general elevation of the whole Colorado Plateau, a process that is still going on. As the plateau gradually rose, shallow rivers that winded across it began to run more swiftly and cut more definite courses. One of these rivers , located east of the upward, was the ancestor of the Colorado. Another river system, called the Hualapai, flowing west of the upward, extended itself eastward by cutting back into the upward, it eventually connected with the ancient Colorado and captured its waters. The new river then began to carve out the 277-mile-long trench that eventually became the Grand Canyon. Geologists estimate that this initial cutting action began no earlier than 10 million years ago. Since then, the Canyon forming has been cumulative. To the corrosive force of the river itself have been added other factors. Heat and cold, rain and snow, along with the varying resistance of the rocks, increase the opportunities for erosions. The Canyon walls crumble, the river acquires a cutting tool. Tons of debris, rainfall running off the high plateau creates feeder streams that carreside canyons. Pushing slowly backward into the plateau, the side canyons expose new rocks, and the pattern of erosion continues. According to the passage, how many miles long was the trench that became known as the Grand Canyon?

A:10,100. B:277. C:14. D:10.

The Grand Canyon Standing on the rim of the Grand Canyon(大峡谷), gazing across this giant wound in the Earth’’s surface, a visitor might assume that the canyon had been caused by some ancient convulsion(震动). In fact, the events that produced the canyon, far from being sudden and catastrophic, simply add up to the slow and orderly process of erosion. Many millions of years ago, the Colorado Plateau in the Grand Canyon area contained 1,000 more feet of rock than it does today and was relatively level. The additional material consisted of some 14 layered formations of rock. In the Grand Canyon region these layers were largely worn away over the course of millions of years. Approximately 65 million years ago the plateau s flat surface in the Grand Canyon area bulged upward from internal pressure, geologists refer to this bulging actions upwarding (弯曲上升) ; it was followed by a general elevation of the whole Colorado Plateau, a process that is still going on. As the plateau gradually rose, shallow rivers that winded across it began to run more swiftly and cut more definite courses. One of these rivers , located east of the upward, was the ancestor of the Colorado. Another river system, called the Hualapai, flowing west of the upward, extended itself eastward by cutting back into the upward, it eventually connected with the ancient Colorado and captured its waters. The new river then began to carve out the 277-mile-long trench that eventually became the Grand Canyon. Geologists estimate that this initial cutting action began no earlier than 10 million years ago. Since then, the Canyon forming has been cumulative. To the corrosive force of the river itself have been added other factors. Heat and cold, rain and snow, along with the varying resistance of the rocks, increase the opportunities for erosions. The Canyon walls crumble, the river acquires a cutting tool. Tons of debris, rainfall running off the high plateau creates feeder streams that carreside canyons. Pushing slowly backward into the plateau, the side canyons expose new rocks, and the pattern of erosion continues. According to the passage, how many miles long was the trench that became known as the Grand Canyon?

A:10,100. B:277. C:14. D:10.