【求助英语基本语法.whenhegoingbacktothehotel,thegirlwasdied.whilehegoingbacktothehotel,thegirlwasdied.uponhegoingbacktothehotel,thegirlwasdied.这3句话有对的么?when是不是只能接一句完整的话,那upon能】

　　求助英语基本语法.

　　whenhegoingbacktothehotel,thegirlwasdied.

　　whilehegoingbacktothehotel,thegirlwasdied.

　　uponhegoingbacktothehotel,thegirlwasdied.这3句话有对的么?when是不是只能接一句完整的话,那upon能接完整一句话么?

　　if和whether意思都为是否的时候,都能起始一个句子么?

　　像：ifyoueverfeltboredabouttravelingtoNYC/whetheryoueverfeltboredabouttravelingtoNYC?这2句是不是都可以?

　　talkabout后面这么用么：wecantalkaboutthatsomestudentshavecultureshockwhileabroad.