来自龚杰的问题
【He______EnglishforthreeyearsbeforehewenttoCanadalastyeara、hadstudiedb、hadbeenstudyingc、studiedd、hasstudied】
He______EnglishforthreeyearsbeforehewenttoCanadalastyear
a、hadstudied
b、hadbeenstudying
c、studied
d、hasstudied

