Frank will fall behind in studies he works hard from now on．（ ）
A．unlessB．becauseC．if
﹣I got a job with Chinese Space Agency．
﹣____．（ ）
A．Have a nice tripB．Good luck
C．Thank goodnessD．Congratulations
﹣Wear your mask before going out．
﹣____．（ ）
A．OKB．OK，I won't
C．Good luckD．With pleasure
﹣The Whites have___Hong Kong
﹣Oh，really？ I have never ____ there before．（ ）
A．been to， goneB．gone to， been
C．been to， gone toD．gone to， been to
﹣____ the population of Tianshui？
﹣It's about 3.6 million．（ ）
A．How manyB．How muchC．What isD．Which is
Let's meet at the school gate，____ ？（ ）
A．shall weB．shall youC．will weD．will you