乳母膳食中缺少优质蛋白，乳汁中（）含量可下降。
A.赖氨酸和苯丙氨酸
B.苯丙氨酸和蛋氨酸
C.蛋氨酸和亮氨酸
D.赖氨酸和蛋氨酸
参考答案：D
He will have learned English for eight years by the time he _____ from the university next year.
A．will graduate
B．will have graduated
C．graduates
D．is to graduate
Windows 98中，软盘使用的文件系统为( )。
A．FAT12
B．FAT16
C．FAT32
D．CDFS
