--Is it convenient to you if I pay a visit to you at 10:00 tomorrow morning? --I' m afraid not. I _____ a lecture then.
________ a difficult situation, so you should send a message to him and give some advice to him .
It was dark______ we arrived at the little town .
—Oh, I failed again —Don’t lose heart. One more time, ________ you will succeed.
Mary does every single bit of housework ______her husband Bob just does the dishes at times.
Tom enjoyed himself so much _____ he visited his best friend in Beijing last year. A. that B which C. when D.where