The problem many children have out of school is getting more and more serious.A. that;drop

问题补充：

The problem many children have out of school is getting more and more serious.

A. that;dropped

B. which;got

C. of;fallen

D. as;run

答案：

(答案→)A. that;dropped

B. which;got

C. of;fallen

D. as;run

解析：problem后是一个同位语从句，因此用that引导，drop out of school是“辍学”之意。