天翼对讲客户目标群主要为外勤人员或车辆较多的行业用户和社会团体，其特征是工作区域范围广，可跨地区呼叫。
参考答案：对
Look! Who on the blackboard? [ ]
A. writes
B. is writing
C. rights
D. are writing
It's very hot. Please keep the door _____.[ ]
A. open
B. opened
C. to open
D. opening
