It’s necessary for you to at least an hour each day to learn the new vocabulary.A. set of

问题补充：

It’s necessary for you to at least an hour each day to learn the new vocabulary.

A. set off

B. set out

C. set aside

D. set down

答案：

A. set off

B. set out

(答案→)C. set aside

D. set down

解析：句意:你每天留出一个小时的时间来学习生词。set off出发；set out出发，开始；set aside留出；set down 记下。根据句意故选C。