The expert says that nowadays there are too many problems linked to poor diet and a of exe

问题补充：

The expert says that nowadays there are too many problems linked to poor diet and a of exercise.

A. limit

B. lack

C. need

D. demand

答案：

A. limit

(答案→)B. lack

C. need

D. demand

解析：A限制；B缺少；C需要；D要求；句意：专家说现在又很多和不好的饮食和缺乏锻炼有关的问题。本句中的a lack of缺少…是一个固定搭配。根据句意说明B正确。