请分别算出70号频点的上行频率和下行频率。
参考答案:
上行频率:890+70*0.2=904MHZ(2.5分)
下行频率:935+70*0.2=949MHZ(2.5分)
用简短的语言依次介绍本单元见识过的几种文体名称。
(1)“书”: _________________
(2)“传”: _________________
(3)“说”: _________________
(4)“序”: _________________
— Hurry up,. The bus is coming.
— Oh, no. we mustn't cross the street ________ the traffic lights are green. [ ]
A. after
B. since
C. while
D. until