甲，乙是周期表中同一主族的两种元素，若甲的原子序数为x，则乙的原子序数不可能是[ ]
A．x+2
B．x+4
C．x+8
D．x+18
答案：B
下列疾病中不会引起吞咽困难的是（）
A.食管溃疡
B.胆囊炎
C.胃食管反流病
D.皮肌炎
E.食管裂孔疝
—Could you tell me _____?
—Sure. It's near the post office on the other side of the street.[ ]
A. when was the built bank
B. when the bank was built
C. where is the bank
D. where the bank is
