【单选题】My cousin is _____________ sometimes. It’s hard for him to change his mind even though his idea is not right.
【单选题】Although he sometimes lost his temper, his pupils liked him______for it.
【简答题】请观看视频17分51秒处,描述 常见的 箱型截面的类型,并说明各自适应什么情况?
【单选题】Mark sometimes ______ to the cinema with his sister.
【单选题】时间常数是指心电图机的输出幅度从 100%下降到 所需的时间。
【单选题】His radio is a very old one. It sometimes works and sometimes it_______
【单选题】用pH试纸测定某无色溶液的pH时,规范的操作是
A.
将pH试纸放入溶液中观察其颜色变化,跟标准比色卡比较
C.
用干燥的洁净玻璃棒蘸取溶液,滴在pH试纸上,跟标准比色卡比较
D.
在试管内放少量溶液,煮沸,把pH试纸放在管口,观察颜色,跟标准比色卡比较