选择填空，从每小题A，B，C，D，四个选取项中选出一个最佳期答案
31．—Which sweater is Mary’s，David／？
—he green one is_________
A．theirs B．his C．hers D．Mine
六、完形填空，阅读下面短文，掌握其大意从每小题A，B，C，D四个选项中选出一个最佳答案
Man has inventedfour kinds of satellites．The first kind of satellites studies the 46 of the earth．They are used to make maps．They also help countries to see where they can 47 oil or gold．
The cecond kind of satellites is used to 48 ships and planes．A ship or a plane can send a message to the satellite and can find out 49 it is．
The third kind of satellites studies the weather ,These satellites 50 clouds and strongwinds moving across the earth．They warn countriesto make preparation when very 51 weather is coming．They 52 of the earth from thousands
