皮皮学，免费搜题
登录
搜题
【单选题】
光束调制中，下面不属于外调制的是（）A.
声光调制
B.
电光波导调制
C.
半导体光源调制
D.
电光强度调制
拍照语音搜题，微信中搜索"皮皮学"使用
参考答案：
参考解析：
知识点：
皮皮学刷刷变学霸
举一反三
【单选题】lt ________ for four days when we arrived, so the roads were very muddy.
A.
was raining
B.
would he raining
C.
had been raining
D.
has rained
【单选题】It ______ for four days when we arrived, so the roads were very muddy.
A.
was raining
B.
would be raining
C.
had been raining
D.
has rained
【单选题】It for four days when he arrived, so the roads were very muddy.
A.
was raining
B.
would be raining
C.
had been raining
D.
has rained
【单选题】Was your journey to Hawaii pleasant last summer? No, it _________ for one week when we arrived, so the roads were very muddy.
A.
has rained
B.
was raining
C.
has been raining
D.
had been raining
【单选题】若凸轮轮廓作用角为2φ,差动角为2αs,为了保证喷油泵换向后供油提前角β不变,则必须满足下列关系 。
A.
2φ = αs –β
B.
2αs = 2φ - 2β
C.
2φ = 2φ - 2β
D.
2αs = 2φ + 2β
【单选题】若凸轮轮廓作用角为2φ，差动角为2α S ，为了保证喷油泵换向后供油提前角β不变，则必须满足下列关系（）
A.
2φ=α S －β
B.
2α S =2φ－2β
C.
2φ=2α S －2β
D.
2α S =2φ＋2β
【单选题】I am standing under Hammersmith Bridge looking at something I have known all my life as a Londoner but am beginning to realise that I don't have a clue about. The River Thames has been here a lot long...
A.
what causes the muddy surface of the River Thames
B.
what children can learn about the history of the River Thames
C.
the diversity offish in the River Thames
D.
what was there under the River Thames
相关题目：