a lot of既可数也可不可数,但是基本上在用到可数的时候用plenty of.
many可数 much不可数
few,可数 little不可数
可数：a numbei of,the number of,many,few ,a few
不可数：huge amounts of,a great deal of,little,a little
两个皆可：some,any,a lot of,lots of,plenty of