These levels come from outside activities that penetrate the classroom structure, from teaching activities, and other noise generated inside, which can be exacerbated by room reverberation.

这些（噪音）可以是穿透教室建筑结构的室外活动声、教学活动的声音以及室内产生的其它各种声响，这些声音都会因为房间的回声效果而被放大。

youdao

It is necessary to do outside activities.

从事课外活动是很有必要的。

youdao

In part, of course, this reflects the heavier workload in Chinese schools, which leaves less time for outside activities.

当然，这部分地反映出中国学校学生课业重，因而很少有校外活动时间的状况。

youdao

They can do many activities outside, like playing sports and swimming at the beach or the pool.

VOA: special.2009.06.22

Iranian intellectuals and opposition activists remain in contact with each other and with the outside world by posting comments and information about their activities on Web sites both inside and outside Iran.

VOA: standard.2009.11.14

The researchers looked at the effects of age, job-related experience, vocational training, outside activities and length of gaps in work history.

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Surveys suggest that academics who engage in outside activities are actually more likely to do their share of teaching than those who don't.

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The purpose of the lab study was to determine whether the distraction created by the temptation of outside activities was indeed what caused a decrease in worker productivity on sunny days.

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