[填空题]
The displacement, s , in metr7,nysdt otlwz18 3;kbes, of a particle t secon g +f) ubgw,,y *t:gnadyt26yhdd.t7xds after it passes through the ory:g6dtgn),2 ,uytxf +7dydat.gwb *higin is given by the expression $ s=\ln \left(3+t-2 e^{-t}\right), t \geq 0$ .
1. Find an expression for the velocity, v , of the particle at time t .
2. Find an expression for the acceleration, a , of the particle at time t .
3. Find the acceleration of the particle at time t=0 .
