L1={ww∣wϵ{a,b}∗}
is context sensitive language (CSL) (since there is infinite string matching in straight order).
L2={wwR∣wϵ(a,b)∗,wRisthereverseofw}
is context free language (since there is infinite string matching in reverse order).
L3={02i∣iisaninteger}=(00)∗
is regular language which contains all strings having even number of 0's
L4={0i2∣iisaninteger}
is context sensitive language (CSL) (since the power is infinite and non linear).