—I wonder if you can join us in the picnic this weekend.—______, for I have too much homework to do.
This is the best way ______ I have thought of ______ the problem.
However difficult you find to arrange your time, it will pay off in the long run.
Walter offered us a lift when he was leaving the office, but our work ______, we didn’t accept the offer.
The job proved to be much more difficult than I______.
It was 300 hundred years ago _______ this historic temple was built by a wealthy Mandarin.