老根中心呈枯朽状或中空的中药材有()
A.黄芪
B.黄芩
C.防风
D.秦艽
E.牛膝
参考答案:B, D
“Shall we stop for lunch _____ shall we drive on?”“Let’s stop for lunch, but the driver can’t drink _____ drive.”
A.and, and
B.or, or
C.and, or
D.or, and
One of my teachers ____ an Englishman. [ ]
A. is
B. are
C. do
D. does