I have finished a large part of the novel written by Dickens, the rest of which ___ very difficult

Peter, Do you remember me—Sure,　Ｉcan’t forget you ________ many years has passed.

Start out right away, _____ you’ll miss the first train[ ]

Why did you collect your CD?—-That day I didn’t see your car, so I _____you’d gone out.

______ has recently been done to provide more buses for the people, a shortage of public vehicles remains a serious problem.