如图，正方形ABCD中，CE⊥MN，∠MCE=40°，则∠ANM=（）
A:40° B:45° C:50° D:55°
如图，正方形ABCD中，CE⊥MN，∠MCE=40°，则∠ANM=（ ）
A:40° B:45° C:50° D:55°
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°.
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°.
如图，已知AB是平面a的一条斜线，B为斜足，AO⊥a，O为垂足，BC是a内的一条直线，∠AB0=45°，∠OBC=45°，则直线AB和直线BC所成的角是（）．
A:45° B:60° C:90° D:120°
如图，已知AB是平面a的一条斜线，B为斜足，AO⊥a，O为垂足，BC是a内的一条直线，∠AB0=45°，∠OBC=45°，则直线AB和直线BC所成的角是（）．
A:45° B:60° C:90° D:120°
如图，PA、PB与圆相切于A和B，C是圆上的一点。若∠F＝80°，则∠ACB＝（）。 
A:45° B:50° C:55° D:60°
单项选择题
