控制新生儿破伤风的措施是（）。

A.优生优育

B.新生儿接种

C.新法接生与孕妇进行破伤风类毒素免疫

D.病例报告

E.加强监测

Tom was about to close the window ______ his attention was caught by a bird.

A．when

B．if

C．and

D．till