问题
选择题
Every few years, the coal workers ___________ their lungs X-rayed to ensure their health.
A．are having
B．have
C．have had
D．had had
答案
答案：B
本题考查时态。根据时间状语every few years,可判断本句应为一般现在时，因此答案选B。句意：每过几年，煤矿工人都要做X射线保证他们的健康。