游离氧化钙测定所用容器必须是（）的，其目的是防止熟料矿物（）而使测定结果（）。
参考答案：干燥；水解生成氢氧化钙；偏高
--- May I visit you at 10 o’clock tomorrow morning?
--- I’m afraid I ______ a document for my boss then. What about 12:00?
A．am preparing
B．will have prepared
C．will be preparing
D．have been preparing
雀替/绰幕枋
