This is〔〕apple.It's〔〕nice apple.A〔an和a〕B〔a和a〕 C〔a和an〕 D〔an和an〕谢谢了,

This is〔〕apple.It's〔〕nice apple.A〔an和a〕B〔a和a〕 C〔a和an〕 D〔an和an〕谢谢了,
This is〔〕apple.It's〔〕nice apple.A〔an和a〕B〔a和a〕 C〔a和an〕 D〔an和an〕谢谢了,

This is〔〕apple.It's〔〕nice apple.A〔an和a〕B〔a和a〕 C〔a和an〕 D〔an和an〕谢谢了,
A an 和 a apple 这样以元音开头的单词前面要用不定冠词an

A this is an apple. Itls a nice apple