Don’t point ________anyone________ your chopsticks. It’s not polite.

A．at ,by

B．at , with

C．to, by

D．out, with

每个窦性心搏后出现一个早搏时应称为( )

A．多源性室早

B．偶发室早

C．二联律

D．频发室早

E．三联律