His younger sister may already be in high school now, in ___ case this picture book is too childish for her.

A．that

B．which

C．whose

D．what

春播时间可在三月中旬至四月（），以出苗不遭晚霜危害为准。

A.上旬

B.中旬

C.下旬

D.中下旬