【单选题】My mother bought me a nice sweater yesterday, now the sweater _______ me. [ ]
【多选题】关于非周期信号幅值谱 |X (ƒ)| 与周期信号幅值谱 |Cn| 下列说法正确的是?
B.
|Cn| 的量纲相当于 |Cn|/ƒ ,即频谱密度
C.
|X (ƒ)| 的量纲相当于|Cn|/ƒ,即频谱密度
D.
|X (ƒ)| 为连续频谱,而 |Cn| 为离散频谱
【单选题】Mother told me in a phone call that she had written to me a week before, but I haven’t received__________.
【单选题】Mother made a promise ____ I passed the college entrance examination she would buy me a mobile phone.
【简答题】Mother gave me a promise_____I made progress in my English she would take me to travel . A that; B that if C that whether ; D whether
【单选题】听力原文:My mother bought me a new pair of shoes.