问题
单项选择题
用气相色谱法测定硝基苯类化合物时，采用（）进行萃取。
A、一氯甲烷
B、二氯甲烷
C、三氯甲烷
D、四氯甲烷
答案
参考答案：B
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用气相色谱法测定硝基苯类化合物时，采用（）进行萃取。
A、一氯甲烷
B、二氯甲烷
C、三氯甲烷
D、四氯甲烷
参考答案：B
| 用方框中词的正确形式填空 。 | |
2. She enjoys____to music. 3. Mr. Smith is a driver. He____very carefully. 4. Daming is listening to the radio and____in the sun. 5.I hope you will have a good time,and see you____. 6. Look! Ann is____for some postcards. 7.-1 am standing on the Great Wall and talking to you. - ？ 8. It's 9:30 p.m.It's time to____. 9. My mother often _presents for my grandmother. 10. There is a boy _for you at the school gate(大门)． |