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问题 单项选择题

下列关于过滤式防毒面具使用说法中正确的是（）。

A.此种面具只适用于有毒气体浓度不超过0.5％的场合

B.只适用于空气中氧含量不太低的场合

C.使用时间可超过2小时

答案

参考答案：B

听力题

At the beginning of the term, a campaign” to be a good student and a good citizen” was launched in our school, and great changes have taken ________ since then.

Before the campaign, we u_____ to be late for school and failed to hand in our homework in t____.Often, we forgot to greet our teachers and after class we ______(发出)loud noises. Worse still, we jumped the quene when waiting ______ buses. However, the campaigns have changed us a lot. We are no longer late for school and more______(认真)in our homework. We have learned to show______(尊敬)for the elders, help others and give up seats to other passengers.

The campaign is a very good experience, from_____ we have learned a lot. More importantly, we have g___rid of many bad habits becoming better students at school and better citizens in_____（社会）
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单项选择题

对象的功能评价值F的含义是( )。

A．评价对象实际实现的功能水平

B．实现功能的最低成本

C．实现必要功能的最低成本

D．功能重要程度
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