chance/happen/seem/appear/pretend to do

there is nobody on playground(seem appear happen used to改写） appear to=seem吗? appear to do? To pretend do not love pretend doing 还是to do remain to be seen为什么等于appear/seem to be feel like seem to 和 appear to 什么区别? happen to 和 chance的区别 seem to do seem to do seem to have done 有这个句型么?S+(seem/appear)+to+(v/adj.) pretend to do 和pretend doing 有啥区别