We go to Tian'anmen Square _____________ Monday. [ ]
A. in
B. on
C. at
D. for
答案:B
犬大量连续采血时,常采用()。
A.颈静脉采血
B.皮下头静脉采血
C.小隐静脉采血
D.心脏采血
恩格尔定律