你好
C 前者强调篮子,一篮
后者是杯子,三杯
桌子下有一篮子苹果.桌子上有三杯牛奶there are three cups of milk
there be句型一般适用就近原则, 就是有最近的名词决定单复数
e.g. There is a book and two pens.
There are two pens and a book.
对于a lot of
要看后面是什么词. 如：
There is a lot of water in the lake.
There are a lot of children in the park.
注意下面两句话：
There is a lot of water and fish in the lake.
There are a lot of fish and water in the lake.