The train will leave at half past six, so I __must__ get there fifteen minutes earlier.
火车六点半开出,所以我必须提前十五分钟到.这里必须要用must,是一定要的意思
希望可以帮到你哦O(∩_∩)O哈!有不会的再问我可用have to 吗？至于这句话，have to也不是不可以，但是must更好其实这里跟你区分一下must和have to，二者都是必须的意思must表示主观，have to表示客观。We must help each other. 强调我们从心里感觉愿意互相帮忙My sister is ill, my mother has to look after her. 由于责任、客观条件要求，而不得不做的事情这个链接的比较全，你可以参考下You don't ____ worry about her .She is much better now.请详细解答.You don't _have to___ worry about her .She is much better now.请详细解答.这里只能用have to，两点原因1.语法上，must 是情态动词，否定式在后面直接加not，应该是mustn't，而不是don’t must2.意思上，mustn't是禁止，条律、规定而不能做。显然不合语意。don't have to翻译成你不必，这句里面她身体已经好多了，所以没有必要担心