They ________ the train until it disappeared in the distance.
—Did you remember to give Jenny the money? —Yes. ________ I saw her, I'm sure.
Although punctual himself, the professor was quite used ________ late for his lecture.
Apples are usually sold by ________ weight and eggs are sometimes sold by ________ dozen.
Professor Zhang gave all the textbooks to all the pupils, except ________ who had already taken them.
Although he sometimes loses his temper, his students like him ________ for it.