about
1. about在用作“不久就要…”解的时候后面通常接不定式，如about to start。但也有接动名词的，如about starting。用不定式比较普通。
about在用作“不久就要…”解的时候不可再加表示时间的词，如不可说about to start next morning或about starng at once。
2. 下面各种表达方式里的about都作“大约”解：
about ten, about a hundred, about half, about a quarter注意ten, a hundred, half和a quarter都是明确的数或量，原来并没有“多少不定”的意思。在有“多少不定”的意思的词语前面不该用about，如不可说about more than ten, about less than half, about several, about some 或about a few等。
虽然about three or four和about a dozen or so等表达方式也有人用，但最好删去about。
3.下面各句里可以有at，也可以没有at，意思并没有区别。有了at, about是副词，没有at, about是介词：
- I went (at) about five (o'clock).
- I went (at) about noon.
- I went (at) about midnight.
- I went (at) about Christmas.
这里at用的少，不用的多。同样地，下面两句里的on和in也用的少，不用的多：
- I went (on) about 18 January.
- I went (in) about January.
- at about five (o'clock), at about noon等不可改作about at five (o'clock), about at noon等。
