—Would you like to play tennis with me _________ it doesn’t rain tomorrow?

  —Sure, _________ I am busy.

A. if; since         B. whether; but    C. if; unless             D. because; until

Hi, my name is Wang Jun. Do you want to know about my staying in America? Well, to tell you the truth, it is really an eye-opening experience here.
In China, I had English classes five times a week since Grade Five. But I didn’t know textbook English could be so different from everyday English until I came to Hotchkiss School, Connecticut. When I first studied English, I was told to say “I’m fine.” when people say “How are you?” But in the USA, I found that people say “I’m good.” or “I’m tired.”
One day, someone greeted （问候） me with “What’s up?” It made me confused. I thought for a moment and then smiled because I didn’t know what to say.
Since then, I have learnt more and more differences between Chinese and American cultures. To my surprise, American girls spend a lot of time in the burning sun getting a tan (晒黑的肤色). In China, girls try every possible way to keep their skin white.
American students are hard-working like Chinese students. In China, schoolwork is almost everything, so we study hard and that’s it. But here, a “good” student not only gets good grades, but also does a lot for the public. That is to say, they get lots of knowledge at school and learn many life skills from social （社会的） work.
【小题1】In China, Wang Jun had _______ English classes every week.

--Your Japanese is so good. How long have you been in Japan?

-- __________ I was five.

A．Since             B．Before            C．Until             D．When