合理的药剂拌种起到（）作用。
A.延迟发芽
B.提高出苗率
C.影响发芽
D.降低发芽率
参考答案：B
—Whose schoolbag is this?
—It _______ be Mary's. It has her name on it. [ ]
A. can
B. may
C. will
D. must
电离层突然骚扰（SID）
