根据语境，用can，may，might，can't，must，mustn't等情态动词填空

1.--need___I take exercise now,doctor? --No.You need to rest.You_must__exercise in three months time. 2.--Oh,how nice the skirt is!_may/can__I try it on? --Yes,of course. 3.--__can/may__I use your dictionary,Kitty? --Of course you__can__,Mill