He stays at home ______ weekends. [ ]
A. at
B. on
C. to
D. in
答案：B
Is this a computer?[ ]
A. Yes, it is.
B. No, it is.
C. Yes, that is.
D. Yes, it's.
据《素问·经脉别论》，在谷食精气的输布过程中未言及的脏是（）
A.肺
B.心
C.肾
D.肝
E.脾
