下列哪种试剂可将NaCl、Na2CO3、(NH4)2SO4、NH4Cl四种溶液区分开[ ]
A.AgNO3溶液
B.BaCl2溶液
C.Ba(OH)2溶液
D.KOH溶液
答案:C
Crusoe found that nine savages seemed to be eating something which they ___ on the fire.
A.have cooked
B.had cooked
C.to have cooked
D.being cooked
少量装卸时,所装卸货物重心离()越远,对吃水差的影响越大。
A.船舶稳心
B.船舶漂心
C.船舶重心
D.船舶浮心