Without the air to hold some of the sun's heat, the earth at night _____,too cold for us to live. [ ]

A. would be freezing cold

B. will be freezing cold

C. would be frozen cold

D. can freeze coldly

出现Cheyne－Stokes和Biots呼吸最主要的机制为（）

A.胸部外伤呼吸受抑制

B.胸腔积液呼吸受抑制

C.呼吸中枢兴奋性降低

D.呼吸肌麻痹

E.严重神经衰竭