1.一个塑料瓶正好能装1kg的水,它一定能装得下1kg的( ) A.白酒 B.酱油 C.花生油 D.汽油 2.(1)Na2CO3与稀盐酸反应放出CO2,但实验室却不用这个反应制备CO2,其主要原因可能是( );已知Na2CO3的溶解度比NaHCO3大,那么在饱和的Na2CO3溶液中连续通入CO2,可观察到的现象是( ) 3.I don't know ( )to visit the old man. A.whether B.if C.that D.which 4.--Does she like to have tea or coffee? --It is unknown ( ) she would like to have, A.how Bas C.that D.which.