题目

句型转换     1．Mr wu told us to leave school at once．The snowstorm got even worse．(用适当的连词合并为一句)        Mr Wu told us to leave school at once __________ the snowstorm got even worse． 2．I like the parrot best because it has colorful feathers．(对画线部分提问)        __________ _____________ you like the parrot best?     3．“Don’t play computer games after schoo1．”Mr Wang warned ns．(改为同义句)       Mr Wang warned us _______ ________ play computer game after schoo1．     4．Baby pandas can not live on th如图1，平面四边形ABCD中，A=π3C=π2，CB=CD=2，且AB=AD．把△ABD沿BD折起（如图2），使二面角A-BD-C的余弦值等于33对于图二，完成以下各小题：（1）求AC的长；（2）证明：AC⊥平面BCD；（3）求直线AC与平面ABD所成角的正弦值．