如图,在Rt⊿ABC中,AB=3,BC=4,∠ABC=90°,过B作BA1⊥AC,过A1作A1B1⊥BC,得阴影Rt⊿A1B1B;再过B1作B1A2⊥AC,过A2作A2B2⊥BC,得阴影Rt⊿A2B2B1;……如此下去,请猜测这样得到的所有阴影三角形的面积之和为( ) A. B. C. D. 答案:D介词、副词填空
—My
grandfather left ______ New York this morning.
—Oh,
I thought he wasn’t going ______ next week.