.碳跟浓硫酸共热产生的气体X和铜跟浓硝酸反应产生的气体Y同时通入盛有足量氯化钡溶液的洗气瓶中(如图装置),下列有关说法正确的是
I tried phoning her office, but I couldn’t _______.
His sister left home in 1998, and _______since.
What do you mean, there are only ten tickets? There _____ be twelve
Could I speak to ______ is in charge of International Sales please?
How much _______ she looked without her glasses!