选择题：机床包括（）几大类（3.0分）1.5 分A、金属切削机床B、特种加工机床C、锻压机床D、木工机床

37.Not until the game had begun ______ the sports ground.　(A)did Peter arrive

20 The expiry in 1999 of the “ ________” was probably the main reason for teamin

5.Supposing the price were lowered, then Tom _____this good cardigan.　(A)will

28[简答题,2.7分] 简述网络安全的概念

8[填空题,10分] 在PowerPoint中，为对幻灯片设置动画效果可单击（）下拉菜单中的“动画方案”命令。