Tokeephealthy，ProfessorJohnson

问题详情：

To keep healthy，Professor Johnson ________ cycling as a regular form of exercise after he retired.

A．took up                           B．caught on

C．carried out                       D．made for

【回答】

A　take up意为“开始从事(某种运动、活动等)”，符合题意；catch on意为“抓牢”；carry out意为“实现”；make for意为“有助于”。

知识点：动词

题型：选择题