1. or表示选择，用于连接词或短语
Harvesting of grains is affected by annual changes in temperature of in the amount of moisture, or both. 粮食的收获受到全年的温度或降雨量的影响，或受两者的共同影响。
2.or用于引导同义词语
A knot is a joining of two pieces of rope or of cord. 结是两根绳子或带子的接合处。
提示：or除了引导如上句中的同义词语之外，还可以引导解释性词语，如an increase of 50p, or 10 shillings in old money(增加50便士，合旧币10先令)。
3.用于构成符合连词whether…or
Whether as statesman, scientist, or philosopher, Benjamin Franklin was destined to gain lasting honor throughout much of the world. 无论是作为政治家、科学家还是哲学家，本杰明·富兰克林注定在世界的许多地方赢得永久的尊敬。
4.在否定句中表示延续否定，用于连接词或短语
In Roman law a woman was known first as her father’s daughter and later as her husband’s wife; she had no name or identity of her own. 根据罗马的法律，女人首先是被当作她父亲的女儿，后来被当作她丈夫的妻子；她自己既没有名字，也没有身份。
提示：or在这种用法中作“也不”解，不能换作and，再如：She can’t read or write. 她不会看书也不会写字。