In English teaching, such mechanical activities as ______ may be helpful for teaching particular structures, but they should not be overused.（  ）

题目：In English teaching, such mechanical activities as ______ may be helpful for teaching particular structures, but they should not be overused.（  ）

A、

transformation and role play

B、

translation and word-matching

C、

gap-filling and topic discussion

D、

memorization and pattern drilling