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【单选题】
When a new mathstopic is introduced,
A.
Astudents answer questions on the board.
B.
Bstudents rely entirely on the textbook.
C.
Cit is carefully and patiently explained to the students.
D.
Dit is usual for students to use extra worksheets.
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参考答案：
参考解析：
刷刷题刷刷变学霸
举一反三
【单选题】The compression of air is finished in the ____ of ramjet.
A.
Intake ducts
B.
Compressor
C.
Turbines
D.
Nozzle
【多选题】The characteristics of ramjet includes: ____.
A.
Complex structure
B.
Inefficient when the aircraft is flying at low speed
C.
Good intake and compression performance when the aircraft is flying at low speed
D.
Usually used in combination with other types of engines
【多选题】The power source of electric power device mainly comes from: ____.
A.
Solar cell
B.
Battery
C.
Wind energy battery
D.
Fuel cell