【简答题】Nowadays, we are in a very______ business environment, (competition)
【简答题】In which of the following situations should we use the expression nowadays? [A] We decide to avoid trouble or er for the future. [B] We try to improve our English for better education. [C] We need...
【简答题】铰链四杆机构有三种基本类型有:( )机构、( )机构和( )机构。
【简答题】铰链四杆机构有()机构、双曲柄机构和双摇杆机构三种基本类型。