架空方式敷设光缆时，一般每个支撑件可固定（）根自承式蝶形引入光缆。
A、4
B、6
C、8
D、10
参考答案：C
酷暑季节，室外工作的工人应多喝[ ]
A．淡盐水
B．碳酸型饮料
C．蛋白型饮料
D．纯净水
I’m told that languagepractising．com is a free website _______learners can not just learn various languages but also chat online．
A．where
B．which
C．that
D．what
