我想你是指在读的时候怎么说吧,因为书写的时候就写2000和2001

2000年:two thousand

2001年:two thousand and one

ninteen ninty eight 1998

(in)year two thousand

(in)year two thousand and one ,or more usually two O O one.

2000:two thousand years

2001:two thousand and one year

1998:ninteen ninty eight

in ninteen ninty eight

in two thousand

in two thousand and one