对因瓦斯浓度超过规定而被切断电源的电气设备，必须在瓦斯浓度降到（）以下方可通电开动。
A、0.5%
B、0.75%
C、1.0%
D、1.5%
参考答案：C
气滞痛的特点是（）
A.游走性，痛无定处
B.阵发性，攻痛无常
C.随情绪波动而时时作痛
D.胀痛
E.持续性固定性胀痛
根据句意，写出括号内所给单词的适当形式。
小题1:My friends in Australia say that they now have beautiful and hot days, with temperatures in the ___________ ( thirty ).
小题2:It is clear that most of the ___________ ( tour ) visiting the small village are from the UK.
小题3:After a night’s work without sleep, he looked much ___________ ( sleep ).
小题4:A dove（鸽子）has a good sense of ___________ ( direct ).
