填方，必须按规定分层夯压密实，取样测定压实以后的干土质量密度，其合格率不应小于（）。
A.85%
B.90%
C.95%
D.98%
参考答案：B
Look, the children are playing ______. They are all very ______.
A．happy, happily
B．happily, happy
C．happily, happily
D．happy, happy
