第1个回答 2013-09-18
I don't know what I shall do next
I don't know (I ) (should ) (do ) (next ).
He didn't decide which bike he would buy.
He didn't decide (he ) (would ) (buy ) (bike ) .
第2个回答 2013-09-18
what to do next
which one to buy
第3个回答 2013-09-18
I don't know what to do next
He didn't decide which bike to buy .
第4个回答 2013-09-18
第一句:I don't know to do what next.
第二句:He didn't decide to buy which bike.