be going to是情态动词吗 能用在过去式里吗

be going to是情态动词吗 能用在过去式里吗 to是介词为什么be going to是情态动词 系动词短语有 be to do和be going to be to do是情态动词短语吗 关于 be going to 的用法例句：I am going to Australia.这个句子的谓语是什么?为什么?be going to 是情态动词吗? to 是情态动词吗 因为后面总是 to be must be是情态动词吗情态动词是什么 怎么才能认出情态动词? be going to do going是动词加ing吗 he will be able to come.这里will是情态动词还是助动词?be able to是实义动词吗? have to是情态动词吗? used to 是情态动词吗? I was going to be all right.为什么总be,be原形不是用在情态动词后面? be going to do里going是动词还是名词? be to 情态动词的用法 be动词与情态动词连用吗? always是情态动词吗I ALWAYS BE HERE. Will+be doing表达应该怎样理解?Will是情态动词,一般后面只接动词原形,will do=be going to do,那will be doing应该怎样理解呢? Will be doing表达应该怎样理解?Will是情态动词,一般后面只接动词原形,will do=be going to do,那will be doing应该怎样理解呢?请帮解释一下,谢谢! 情态动词还是将来时We _ careful in doing this kind of work.A.have to B.will be going to be C.should have to be D.shall have to be Dshall是情态动词还是表示将来时?为什么不选CC不是完成时啊!