seven thirty/half past seven;seven thirteen,seven o'clock.表整的时刻都是用数字再加上o'clock.
明早八点就是at eight o'clock tomorrow morning.注意：表达“在几点”时刻前要用介词at.January the first/Jan.1st(缩写),January the second/Jan.2nd(缩写)；January the third/Jan.3rd；January the fourth/Jan.4th,January the fifth/Jan.5th.此后同理.Jan.6th,Jan.7th,Jan.8th...就一号、二号、三号不一样.
因为序数词里第一,第二,第三是不规则的,其它都是以th结尾.fourth,fifth,sixth,seventh,eighth,ninth,tenth.