Migration is the dynamic ______ of population's change:everyone's
solution,everyone's conflict.
A. undertaking B. underwater C. undertow D.underweight
上期习题答案：
The central provinces have floods in some years, and ____________.
A. drought in others B. droughts are others C. while others droughts D. others in drought
答案：A
本句是一个并列句，因此连词and后相同的谓语词have被省略了。