wait for sb/sth (for)a long time.前一个for不能省.
for 句首时不能省.for all day.all前for必须省去.
原句时态可否改为:He must have waited (for) a long time. In fact, he waited for two hours.
wait for sb/sth (for)a long time.前一个for不能省.
for 句首时不能省.for all day.all前for必须省去.
原句时态可否改为:He must have waited (for) a long time. In fact, he waited for two hours.