Anyone can borrow books from this library _______ he keeps them clean and returns them in time.
Sam ______ some knowledge of the computer just by watching others working on it.
Before the sales start, I make a list of ______ my kids will need for the coming season.
That’s the new machine ______ parts are too small to be seen.
---Do you think you could do it without help? ---______. This is not the first time for me.
---Perhaps we can’t arrive at the bus station on time. --- .We still have forty minutes.