SF6气瓶内的压力降到（）MPa时，应停止充气，因剩余的气体含水量及杂质较高。
A.0.05
B.0.1
C.0.5
参考答案：B
选词填空。
Last summer, Lingling went to Xinjiang 1.______ (with/and) her parents. Xinjiang is in the 2.
(east/west) of China. She 3._______ (ride/rode) a horse. She 4. _ (climbs/climbed) the Tianshan
Mountain. She 5.______ (visited/looked) the Tianchi Lake. It 6._ (was/were) very beautiful. She
7. ______ (have/had) a lovely time.
估一估，得数大于400的算式是[ ]
A.345+98
B.875-482
C.208+169
