Question

your hair needs 为什么用to be cut 而不用being cut 有重谢

your hair ____,you'd better have it done tomrrow为什么用to be cut那么用being cut 为什么不行

Answer 1

need doing sth 等于 need to be done
表示被动意思 ，可以用 to be cut .

Answer 2

人＋need ＋to do
物＋need ＋doing
物＋need ＋to be done

Answer 3

need 后面要加 to do 不定式