My parents ( were ) young twenty years ago.
twenty years ago 20年前,过去式,主语复数,所以用were
Now They ( are ) old..I love them very much.
一般现在时 are
1.work-- works-- worked--- working
2.go--goes-- went-- going
3.ask-- asks--- asked--- asking
4.make--- makes--- made--- making
5.do--- does--- did--- doing
6.have --- has--- had--- having
7.stop-- stops--- stopped---stopping
8.eat --- eats---ate----eating
9.drink-- drinks--- drank --- drinking
10.sing-- sings--- sang---singing
11.fly --- flies--- flew--- flying
12.swim--- swims---swam---swimming
祝开心!