As we all know bad eating habits and a of exercise may lead to health problems .A. lackB

问题补充：

As we all know , bad eating habits and a of exercise may lead to health problems .

A. lack

B. limit

C. need

D. demand

答案：

(答案→)A. lack

B. limit

C. need

D. demand

解析：考查动词。lack缺少；limit限制；need需要；demand要求。句意：我们都知道，不良的饮食习惯和缺少锻炼会导致健康问题。