No one wants you to be _______ but we really want you to do your best always.

A．proud

B．perfect

C．polite

D．popular

环磷酰胺的性质为（）.

A．水溶液不稳定，易水解脱氨 

B．灼烧后产生硫化氢气体，使醋酸铅试纸呈黑色 

C．遇丙二酸及醋酐，加热后显红棕色 

D．加氢氧化钠液温热后即显紫色 

E．在碱性条件下，糖类能加速其溶液的水解