--Who's the man shaking hands with our headmaster?

--A scientist ____________ to give us a talk on the history of the Party.

A．is invited

B．invited

C．inviting

D．which is invited

动脉导管未闭出现肺动脉高压时临床检查不会出现（）

A.肺动脉第二音增强

B.左心底连续性杂音

C.声音嘶哑

D.心电图示右心室肥大

E.X线检查示肺动脉段突出