You should do _best to finish your work on time A.yours B.yourselves C.your

C
You should do【your】best to finish your work on time
句型：one‘s best to do sth 尽某人的全力做某事
用物主代词your 修饰best
意为你应该尽你的全力去准时完成你的工作You can see many flowers here and there in our school. A. a kind of B. plenty of C. a lot ofB 大量（你想问什么？）C也是许多的意思为什么不能选C. a lot of不是都能修饰不可数名词和可数名词吗？？？？是的，所以我觉得B、C都可以我所知道的区别：plenty of较lots of正式plenty of指某物足够多，完全满足需要，lots of没有这层意思，如：plenty of time充足的时间lots of time很多时间（也许还不够用）不过我建议用C，这要看是几年级的题目了，一般是选C