实验过程中，开启炉门进行操作时，必须先断电；炉门打开时间不宜过长，以免引起炉膛开裂，实验完毕，立即断掉电源。
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实验过程中，开启炉门进行操作时，一定要带隔热手套
A. 对
B. 错
You are free to choose any location you like.
A. 对
B. 错
Translatingmarketing materials is unnessary in terms of international fairs.
A. 对
B. 错
The interpreter you hire might be a professional freelancer or you may also hire one in a trustworthy translation company.
A. 对
B. 错
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