they are very tired.why [don't they,not they,do they,not to] have a rest

they are very tired.why [don't they,not they,do they,not to] have a rest
they are very tired.why [don't they,not they,do they,not to] have a rest

they are very tired.why [don't they,not they,do they,not to] have a rest
they are very tired.why [don't they] have a rest?

don't they

They are very tired.why don't they have a rest.

选don't they
not they和not to不对.应该是not
do they也不对,这样句子就成了:为什么他们要休息,与前一句矛盾

选第一个的，why don't do

A 他们不是诚实的 他们不值得去知道真相 他们不诚实，他们没资格知道真相，A， 他们并不可靠。不应知道真相