问题
单项选择题
一氧化碳含量在（）mg/m3时操作人员连续工作时间不超过30min。
A、50
B、100
C、200
答案
参考答案：B
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一氧化碳含量在（）mg/m3时操作人员连续工作时间不超过30min。
A、50
B、100
C、200
参考答案：B
| 完形填空。 | |||
| Ampere 1 _a famous scientist. He liked to 2_ himself busy all day long both at home and in his office. Sometimes he found _3 _ery hard to work for a long time because many visitors came to talk to him at home. In order to have fewer visitors, Ampere thought of an idea. He put up a plate on the gate. On the plate he wrote 4__ords, "Mr. Ampere isn't at home." One day he went home from his office late in the afternoon. When he 5__is gate, he saw the plate and read it, and then be said to himself, "Oh, yes, Mr. Ampere isn't in." _6_hat he returned to his office. 7_ time, Ampere went to give a talk at a meeting. On his to the meeting hall, he passed by a river. He picked up a stone, and played with the stone in his hand and then put it _8__is pocket. Before he left the river, he took "the stone" out of his pocket and threw it back into the river. During the meeting, when Ampere wanted to see what time _9_ he was surprised to find the "watch" he took out of his pocket was not a watch, 10_stone. | |||
| ( )1.A.is ( )2.A.keep ( )3.A.that ( )4.A.this ( )5.A.got ( )6.A.Said ( )7.A.Other ( )8.A.into ( )9.A.it is ( )10.A.but | B.was B.stay B.this B.that B.got to B.With B.Another B.to B.it was B.and | C.has C.live C.it C.these C.arrived C.And C.The other C.with C.was it C.is | D.to be D.let D.its D.these D.arrived in D.after D.Others D.from D.is it D.only |