【C18】______A．walksB．exerciseC．tripsD．housework

【C18】______A．involvingB．involvedC．containedD．containing

用HPLC法分析生物碱成分，固定相采用C18色谱柱时，属于____色谱，常用的中性流动相是____溶液。

All you do now is ______ the housework before your mom arrives home.A．having finishedB．fin

Mother is ill. Who will ______ the housework？A、take afterB、take upC、take outD、take over

Today, housework has been made much easier by electrical______.A．facilitiesB．appliancesC．a

Apart from caring for her children she has to take on such heavy__________ housework as ca