How long ________ they ________ (dig) the ditch?
have … been digging
暂无解析
Onlywhenyouhaveobtainedsufficientdata________cometoasoundconclusion.
Iwishyou________likethat.
Ifound________toanswerallthequestionswithinthetimegiven.
You________gonow.It’sgettinglate.
To succeed in a scientific research project ________.
