《三驼图》的作者是下面哪一位（）
A.李士达
B.郑燮
C.徐渭
D.唐寅
参考答案：A
The parents were in search _______ their son who was lost when the two countries were ______ war.
A．of; in
B．of; at
C．for; at
D．for; in
制氢设备氢气系统中，气体含氧量不应低于（），含氧量不应超过（）。
A、99.5%，0.5%
B、98%，2%
C、96%，2%
