单项选择题
On May 30th, 2010, at（）World Table Tennis Championship, Ma Lin and Zhang Joke won the gold medal in men’s with（）score of 3:1.
A.a; aB./; theC.a; /D.the; a
单项选择题 （）from space，the earth，with water（）seventy percent of its percentage，looks like a “blue ball.”
单项选择题 Though the book is a little expensive，it is（）.
单项选择题 It is required that students（）mobile phones at school，so seldom（）them using one.
