_______ to ride a bike from your school to the park?
A:How long did you spend
B:How far did it take
C:How long did it take you
D:How far did you spend
为什么要控制二氧化碳的排放量?你是怎样响应低碳生活号召的?
在Rt△ABC中,∠C=90°,∠A=30°,AB=4,则AC=____