皮皮学，免费搜题
登录
搜题
【单选题】
由氢原子理论可知, 当氢原子处于n＝3的激发态时, 可观察到可见光谱线为A.
一种波长的可见光
B.
二种波长的可见光
C.
三种波长的可见光
D.
各种波长的可见光
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】“Please don’t forget ______ the door when you leave.” “No, I won’t forget ______ it.”
A.
to lock; to lock
B.
to lock; locking
C.
locking; to lock
D.
locking; locking
【简答题】历史曲线的数据来源是_____________。
【单选题】9) Why wouldn’t the car start if the driver returned to the carvery soon ? A) Because it had used its vapor lock. B) Because its vapor lock was too cold. C) Because its vapor lock hadn’t cooled down. ...
A.
Because it had used its vapor lock.
B.
Because its vapor lock was too cold.
C.
Because its vapor lock hadn’t cooled down.
D.
Because the car was tired from running.
【单选题】Don’t forget to lock the door , _____ ?
A.
do you
B.
don’t you
C.
will you
D.
won’t you
【单选题】— You didn't lock the back door. — You are wrong. I ______. [ ]
A.
have locked it
B.
lock it myself
C.
did lock it
D.
do lock it
相关题目：