【单选题】--Do you think you will give me a hand in time of trouble? --I’d like to do something for you ______ everything you’ve done for me.
【单选题】I’d like to do something for you ____ everything you’ve done for me.
【简答题】对于实数 ,有下列命题: ①若 ,则 ; ②若 ,则 ; ③若 ,则 ; ④若 ,则 ; ⑤若 , ,则 . 其中真命题是____(填序号).
【单选题】因链轮具有多边形的特点,链传动的运动表现为( )
【简答题】定义“正对数”: ,现有四个命题: ①若 ,则 ; ②若 ,则 ; ③若 ,则 ④若 ,则
【简答题】In August we play tennis every day. In August we play tennis all day. ____