问题详情：
![Tokeephealthy，ProfessorJohnson]( "Tokeephealthy，ProfessorJohnson")
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
