Lucy's friends play volleyball (改否定句，说明原因）

Lucy's friends don't play volleyball.

Lucy的朋友们玩排球
...改为否定，则是不玩排球~所以否定动词 do sth变为do not do sth

Their father does not go to Beijing

第三人称单数，所以改为 does not

应该改为Lucy's friends don't play volleyball.因为在该句中动词是play，而该词没有否定式，故只能用助动词do，加 not表否定。所以，原句就改为Lucy's friends don't play volleyball.谢谢。

Lucy's friends don't play volleyball.
friends 是复数，所以用do not.

Lucy's friends don't play volleyball.
friends 是复数，所以用do not.