【判断题】合金浇注温度较低、压铸模具温度较低,压射比压可选低些
【单选题】When I came into the room,he pretended ________ his homework.
【简答题】The driver is ________________________.
【判断题】流体流动过程中阻力损失是由静压能提供的。 ( )
【单选题】猪链球菌病时,心瓣膜上可出现菜花状赘生物,其性质是
【单选题】I didn't know him well.I __never met him before.
【单选题】马小虎同学做了一道因式分解的习题,做完之后,不小心让墨水把等式:a 4 -■=(a 2 +4)(a+2)(a-▲)中的两个数字盖住了,那么式子中的■、▲处对应的两个数字分别是( )