在SQL语言的SELECT语句中,用于对结果元组进行排序的是哪一个子句______。
A.GROUP BY
B.HAVING
C.ORDER BY
D.WHERE
参考答案:C
Which do you prefer to use to keep in touch with your friends, QQ______ WeChat?
A.or
B.and
C.so
D.but
对人体安全的电压应不高于 V。