The young dancers looked so charming in their beautiful clothes that we took______pictures of them.
A.many ofB.masses ofC.the number ofD.a large amount of在线课程B
解析：
选A应该去掉of; the number of…的数量；
a large amount of修饰不可数名词。B="lots" of既可以修饰可数名词也可以修饰不可数名词。句意：那些穿着美丽服装的年轻的舞蹈演员看上去是如此的迷人以至于我们拍了很多他们的照片。