There is a shortage of teachers in Western China and it will fall on the 80s and 90s gene

问题补充：

There is a shortage of teachers in Western China, and it will fall on the 80s and 90s generations to this responsibility.

A. take on

B. step up

C. make up

D. apply for

答案：

(答案→)A. take on

B. step up

C. make up

D. apply for

解析：句意：在中国西部缺少教师，承担这个责任会落在80后和90后的身上。四个选项的意思分别是：A. take on承担，雇佣，呈现，B. step up加紧，C. make up 组成，化妆，弥补，D. apply for申请，应用，根据句意选A。