He started to learn English in 1990 and in the years ________ he kept on using it in his work.

A．following

B．followed

C．follow

D．that followed

有关呼吸系统体征，下列描述正确的是（）

A.深麻醉时分钟通气量显著降低

B.乙醚麻醉第四期出现呼吸麻痹

C.呛咳和支气管痉挛常为麻醉过浅的表现

D.呼吸系统体征受肌松剂的影响

E.以上均是