Ⅰ.单句语法填空
1．We must mark ______ the tennis court ready for the match these days.
【答案】 out
2．Eminent physicists from all over the world came to the US ______(celebrate) the centennial of Einstein's birth.
【答案】 to celebrate
3．He pretended ______(study) when his mother stepped into his room.
【答案】 to be studying
4．He asked so many questions that I got completely ______(confuse)．
【答案】 confused
5．With everyone's face ______(hide) behind the mask，it's hard to tell who they really are.
【答案】 hidden
