The professor with a number of students was doing experiments in chemistry lab at that time.
句子的主语是单数，尽管后面带有with, as well as, rather than, like, but, except, besides和along等连接的名词，谓语仍用单数形式。但在口语中，有时根据观念一致的原则，谓语可以用复数形式。连词or, either...or, neither...nor, whether..or, not only...but also和not...but等连接并列主语，谓语的单复数依从临近原则来决定。关系代词who, that, which等在定语从句中做主语，谓语动词的数应与先行词的数一致。
(1)A cart and horse was seen in the sistance.
(2)Nobody except Miss Mary is to join us.
(3)Not one but all of us are hoping to be there.
(4)None of our parents is a driver.
语法分析：在由noen, either, no和one等作主语时，谓语动词一般用单数形式。
(5)Lots of damage was caused by the flood.
语法分析：a lot of, lots of等+名词构成的主语，谓语动词的数依据主语部分中后面的名词数而定。
(6)Where is your teacher and classmates?
1. Where [be] the watch and chain?
2. Smoke and fod [be] often called clever.
3. She, like you and Tom, [be] very clever.
4. The teacher with some of her pupils [be] cleaning the classroom.
5. You or I [be] going to receive them this afternoon.
6. Many a desk and many a bench [be] to be taken out of the room.
7. More than one [be] killed in the battle.
8. Part of the students here very clever.
9. A number os pages in the book [be] broken.
10. The number of students [be] boys in our classroom.
11. One-third of the students [be] boys in our classroom.
12. Four million frances [be] very hones and hard-working.
13. The goverment [be] very honest and hard working.
14. Mankind [make] progress.
答案：1. is 2. is 3. is 4. was. 5. am 6. is 7. was 8. are 9. are 10. is 11. are 12. is 13. are 14 has been making.