His physical disability makes _____ rather difficult for him to find a good job.
There used to be a mountain in our village, at the top of which ________.
It was along the Mississippi River ________ Mark Twain spent much of his childhood.
Linda,make sure the tables ________ before the guests arrive.
________caused the accident is still a complete mystery.
—May I borrow your computer? —Sorry, it is ________ at the moment.