赖氨酸
A．酸性基B．碱性基C．芳香基D．含硫基E．脂肪族支链下列氨基酸侧链分别属上述何种基团
参考答案：B
The reason_____ he explained to us was ______he was ill.
for; that B. for ; because C. why; that D. which; that
布、跳线施工中，数据类业务宜选用（）或超五类线。
A.五类线
B.三类线
C.一类线
D.二类线
