帮我检查:He tried his best to solve the problem,( )帮我检查:He tried his best to solve the problem,( )difficult it was.a.howeverb.no matterc.whateverd.although

问题描述:

帮我检查:He tried his best to solve the problem,( )
帮我检查:
He tried his best to solve the problem,( )difficult it was.
a.however
b.no matter
c.whatever
d.although

a.
or: no matter how

a