A-A+
(Those of us) who work in chemical (laboratori
问题详情
(Those of us) who work in chemical (laboratories) should have (their) lungs (checked) quite regularly.
A．Those of us
B．laboratories
C．their
D．checked
参考答案
正确答案：C
解析：应改为our，代指前面的those of us。
考点：
