A proton is an elementary particle of matter.质子是物质的基本粒子。an elementary English course基础英语课程Their course of study includes elementary hygiene and medical theory.他们的课程包括基础卫生学和医疗知识....
In most languages adjectives have slightly different spellings for masculine and feminine.在多数语言中，形容词的阳性和阴性的拼法略为不同。There are so many variant spellings of his name.他的名字有很多不同的拼写形式。Efforts to sandardise English spellings hav...