John still can't work out the problem __I have helped him several times.A because B even C since D though选啥?为什么不选C
问题描述：
John still can't work out the problem __I have helped him several times.
A because B even C since D though
选啥?
为什么不选C
答
D吧
答
D
尽管我帮了他很多次，约翰始终不能解决这难题。
答
D though
虽然我已经帮了他几次,John仍然解不出那个问题