The very ubiquity of electronic communications can have a surprising downside, notes Richard Kohn, a military historian at the University of North Carolina: a wife becomes accustomed to frequent e-mail from her husband, until he can’t get to a computer. And then her anxiety increases.()

A. failure

B. underside

C. drawback

D. consequence

恒温恒湿空调机的温度控制精度为（）℃。

A.+-0.5

B.+-1

C.+-1.5

D.+-2