今年父亲的年龄是女儿年龄的4倍,3年前父女年龄之和是49岁。求父女今年各是多少岁?
女儿的年龄:(49+3+3)÷5=11(岁);父亲的年龄:11×4=44(岁)
----what do you think of the Chinese language today?
----Quite popular. It______ in communicating with other countries. More and more foreign friends are learning Chinese.
A.plays an important role
B.is playing an important role
C.has played an important role
D.is being played an important role
以下哪些属于拌和站信息管理系统的一部分()。
A、拌和站采集和传输设备;
B、数据签名锁;
C、拌和站信息管理系统网络平台;
D、移动基站。