英语的介词总共有多少?分别是哪些?答:另外, 由last, next, this, that, these, those等词构成的表示时间的短语前面, 通常不用任何介词。yesterday, today, tomorrow, tonight等词前面也通常不用介词。例如:He bought a Chinese-English dictionary this morning.They traveled to Beijing last summer.You'd better finish your homework ...