用括号里的词的适当形式填空。

1.I’d like ______ (organize) a party.

2.She _______ (play) the piano for 2 hours.

3.When I was twelve,I _______ (start) to play tennis.

4.My brother has been swimming since he _______ (be) 7 years old .

5.Their apartment is on the _______ (nine) floor of the building .

6._______ (luck)，Fred was not hurt in the car accident .

右心导管检查发现肺动脉血氧含量较右心室高，提示

A．右向左分流

B．肺动脉高压

C．肺动脉狭窄

D．房间隔缺损

E．以上都不是