单位脉冲函数δ(t)傅氏变换为（ ）
A. π[δ(ω+ω0)+ δ(ω-ω0)]
B. πj[δ(ω+ω0)+ δ(ω-ω0)]
C. 1
D. 1/(jω)+ πδ(ω)
若f(t)的Fourier变换为F(ω),则f(t+1)的Fourier变换为()
A. ejωF(ω)
B. e-jωF(ω)
C. F(ω+1)
D. F(ω-1)
U7T2Match the following expressions with Chinese counterparts. Pls refers to Text 2 in Unit 7.
Why should we consider climate change when making economic decision?
A. Because it tells us much about future risks.
Because it promotes scientific advancement
C. Becauseit has huge potential significance.
D. Because it helps us avoiding making wrong decisions.
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