.As is known to all,____ tiger is in____ danger of dying out.
| A．a; a | B．the; / | C．a; / | D．the; the |
Scientists have many theories about how the universe ___ into being.
| A．came | B．was coming |
| C．had come | D．would come |
She'll never forget her stay thereshe found her son who had gone missing two years before.
| A． | that | B． | which | C． | where | D． | when |
My uncle’s house in the downtown area is much smaller than ours , but it is twice _______ expensive . 
| A．as | B．so | C．too | D．very |
—You speak very good French!
—Thanks. I __________ French in Sichuan University for four years. 
| A．studied | B．study | C．was studying | D．had studied |
The teacher together with the students ________ discussing Reading Skills that ________ newly published in America.（）
| A． | are; were | B． | is; were | C． | are; was | D． | is; was |