后面
质量为60kg的人，以8km／h的速度从后面跳上质量为80kg、速度为2.9km／h的小车，则小车的运动速度变为____m／s．若人迎面跳上小车，则小车的速度变为____m／s．
质量为60kg的人，以8km／h的速度从后面跳上质量为80kg、速度为2.9km／h的小车，则小车的运动速度变为\_\_\_\_m／s．若人迎面跳上小车，则小车的速度变为\_\_\_\_m／s．
Mary found _____ extremely difficult to pass the examination.
Mary found \_\_\_\__ extremely difficult to pass the examination.
学院为每个学生提供 次免费查重机会，需要多次查重的学生，后面每次查重需要缴费才能进行。（ ）
学院为每个学生提供 次免费查重机会，需要多次查重的学生，后面每次查重需要缴费才能进行。（ ）B
After a few weeks with him, I felt sorry for to be unfriendly to him at first.
After a few weeks with him, I felt sorry for to be unfriendly to him at first.
He insisted that he _____ in good health and _____ to work there.
He insisted that he \_\_\_\__ in good health and \_\_\_\__ to work there.