预防地方性甲状腺肿宜采用的措施是（）。
A.口服他吧唑
B.食盐碘化
C.口服左旋甲状腺素
D.放射性131I治疗
E.手术治疗
参考答案：B
— Look at the sign on the right.
— Oh, smoking ____ here. [ ]
A. doesn't allow
B. isn't allowed
C. didn't allow
D. wasn't allowed
Tell me ________ how it came about that you were 20 minutes late for class. You needn’t go into details.
A．in advance
B．in vain
C．in total
D．in brief
