某三相电路中．三个线电流分别为：i_A=18sin（314t+23°；）i_B=18sin（314t+23°；）i_C=18sin（314t+23°；）当t=10s时，三个电流之和为（）A。

B:18 C:9 D:2

水平角观测中，盘左起始方向OA的水平度盘读数为358°12＇15＂，终了方向OB的对应读数为154°18＇19＂，则AOB前半测回角值为： （）

A:156°06＇04＂ B:-156°06＇04＂ C:203°53＇56＂ D:-203°53＇56＂

已知预应力锚索的最佳下倾角，对锚固段为β1=ψ-α，对自由段为某滑坡采用预应力锚索治理，其滑动面内摩擦角ψ=18°，滑动面倾角α=27°，方案设计中锚固段长度为自由段长度的1/2，问依据现行铁路规范全锚索的最佳下倾角β计算值为以下哪一数值（）

A:9° B:12° C:15° D:18°

某岩石边坡代表性剖面如下图，边坡倾角270°，一裂隙面刚好从边坡坡脚出露，裂隙面产状为270°∠30°，坡体后缘一垂直张裂缝正好贯通至裂隙面。由于暴雨，使垂直裂缝和裂隙面瞬间充满水，边坡处于极限平衡状态（即滑坡稳定系数Ks=1.0）。经测算，裂隙面长度L=30m，后缘张裂缝深度d=10m，每延米潜在滑体自重G=6450kN，裂隙面的黏聚力c=65kPa，试计算裂隙面的内摩擦角最接近下列哪个数值？（坡脚裂隙面有泉水渗出，不考虑动水压力，水的重度取10kN/m3）（）

A:13° B:17° C:18° D:24°

Passage Five
Temperatures on December 12
City High Low
Cleveland .................. 37° 31°
Columbia, S. C ............ 60° 27°
Columbus, Ohio ............ 41° 34°
Dallas .................... 81° 50°
Dayton. ................... 41° 33°
Decatur ................... 39° 30°
Denver .................... 49° 33°
Des Moines ................ 34° 27°
Detroit ................... 37° 28°
Dubuque ................... 30° 23°
Duluth .................... 19° 10°
Eau Claire ................ 24° 19°
El Paso ................... 79° 36°
Evansville ................ 52° 36°
Fairbanks ................. -31° -40°
Fargo ..................... 17° -2°
Flint ..................... 31° 26°
Flagstaff ................. 56° 31°
Great Falls ............... 14° 3°
Grand Rapids .............. 33° 26°
Green Ray ................. 24° 20°

What was the high temperature in Columbus, Ohio on December 12（）

A:81°. B:50°. C:41°. D:60°.

Passage Five
Temperatures on December 12
City High Low
Cleveland .................. 37° 31°
Columbia, S. C ............ 60° 27°
Columbus, Ohio ............ 41° 34°
Dallas .................... 81° 50°
Dayton. ................... 41° 33°
Decatur ................... 39° 30°
Denver .................... 49° 33°
Des Moines ................ 34° 27°
Detroit ................... 37° 28°
Dubuque ................... 30° 23°
Duluth .................... 19° 10°
Eau Claire ................ 24° 19°
El Paso ................... 79° 36°
Evansville ................ 52° 36°
Fairbanks ................. -31° -40°
Fargo ..................... 17° -2°
Flint ..................... 31° 26°
Flagstaff ................. 56° 31°
Great Falls ............... 14° 3°
Grand Rapids .............. 33° 26°
Green Ray ................. 24° 20°

What was low temperature in Flagstaff on this day（）

A:26°. B:-2°. C:3°. D:31°.

Passage Five Temperatures on December 12 City High Low Cleveland .................. 37° 31° Columbia, S. C ............ 60° 27° Columbus, Ohio ............ 41° 34° Dallas .................... 81° 50° Dayton. ................... 41° 33° Decatur ................... 39° 30° Denver .................... 49° 33° Des Moines ................ 34° 27° Detroit ................... 37° 28° Dubuque ................... 30° 23° Duluth .................... 19° 10° Eau Claire ................ 24° 19° El Paso ................... 79° 36° Evansville ................ 52° 36° Fairbanks ................. -31° -40° Fargo ..................... 17° -2° Flint ..................... 31° 26° Flagstaff ................. 56° 31° Great Falls ............... 14° 3° Grand Rapids .............. 33° 26° Green Ray ................. 24° 20°

What was low temperature in Flagstaff on this day（）

A:26°. B:-2°. C:3°. D:31°.

Passage Five Temperatures on December 12 City High Low Cleveland .................. 37° 31° Columbia, S. C ............ 60° 27° Columbus, Ohio ............ 41° 34° Dallas .................... 81° 50° Dayton. ................... 41° 33° Decatur ................... 39° 30° Denver .................... 49° 33° Des Moines ................ 34° 27° Detroit ................... 37° 28° Dubuque ................... 30° 23° Duluth .................... 19° 10° Eau Claire ................ 24° 19° El Paso ................... 79° 36° Evansville ................ 52° 36° Fairbanks ................. -31° -40° Fargo ..................... 17° -2° Flint ..................... 31° 26° Flagstaff ................. 56° 31° Great Falls ............... 14° 3° Grand Rapids .............. 33° 26° Green Ray ................. 24° 20°

What was the high temperature in Columbus, Ohio on December 12（）

A:81°. B:50°. C:41°. D:60°.