He wondered __________ the pyramids were built.
______ is it _____ has made Peter _____ he is today?
If _____ carefully, the experiment will be successful.
It would be a good idea to use a plastic bottle, ___cut off, as a container to grow young plants in.
The judge paid no attention to _____ he had just lost his wife.
Who would you rather ______ the report instead of you?