高中英语语法2道
My sister,an inexperienced rider,was found sitting on the bicycle____to balance is.
A.having tried
B.trying
C.to try
D.tried
请问这道题为什么选A不选B
If there is a lot of work______.I’m happy to just keep on until it if finished.
A.to do
B.to be doing
C.done
D.doing
请问这道题为什么选B不选A