问题 a matter of 是不是大约的意思？红色部分在句子中作什么成分？

The differences in athletic performance might be not very large,a matter of noly a few percent.

问题 当前一句出现two，后一句是用a还是one

Every “Number of freeze-thaw cycle” in the table corresponding to two samples including a/one parallel sample.表中每一个冻融循环次数对应两个样本，包括一个平行样本，我是想问这里的一个，用a好还是one好？我是想前面用了two后面是不是用one好一...

问题 ​As a board member for/of....

As a board member for the Internet Security Research Group, she always has her pulse on the industry.这里为什么用for而不是of呢？

问题 ​As a board member for/of....

As a board member for the Internet Security Research Group, she always has her pulse on the industry.这里为什么用for而不是of呢？

问题 good exercise与a good exercise

Swimming is supposed to be _____ very good exercise for older people. 这里到底能不能加不定冠词a？有的人说能加不定冠词，有的人说不能加不定冠词。请教各位。谢谢！

话题 every once in a while

话题 be in for a shock

话题 a full-fledged home

话题 A King in New York

话题 a little bit late home

话题 a home away from home

话题 while still a young man

话题 within a couple of years

话题 the homecoming of a lifetime

话题 a great deal of me.