单项选择题
Activity Two: Writing Practice A head-teacher is s...
单项选择题Activity Two: Writing Practice A head-teacher is speaking to a teacher in her school. “Next week we’re going to clean the school as follows: Classroom Building 1 on Monday. Building 2 on Tuesday. The computer room and sound lab on Wednesday. The science labs on the Thursday. The library and the Teachers’ Rooms on Friday. Please write a notice for the students and put it up. Thank you.” Work with your partner and write a large notice. Start like this: Classroom Building 1 will be… Does Activity Two has a communicative purpose? A、正确 B、错误
实际光波产生干涉的三个必要条件，两叠加光波 相同、振动方向相同、相位差恒定。
问答题实际光波产生干涉的三个必要条件，两叠加光波 相同、振动方向相同、相位差恒定。
夏天吃冰激凌，撕开包装，冰激凌会冒“白汽”，下列对“白汽”的来源解释正确的是（）。A. 冰激凌融化产生“白汽”...
单项选择题夏天吃冰激凌，撕开包装，冰激凌会冒“白汽”，下列对“白汽”的来源解释正确的是（）。
