2.exist vi. ____________________
Man can’t ______without air.(没有空气人就不能生存)
火星上有生命吗？___________________________________________?
拓展：存在 n._______ _________
bring…i nto existence ____________________
come into existence=come into being ___________________
(1). An information bureau was brought _______existence to deal with inquiries.
(2) When did this world come _______existence?
3.puzzle n/v.
(1) n. ______________
a cross word puzzle _____________
I was in a _______about the matter.(我对这件事迷惑不解)
(2) vt. _____________
The question puzzled me.=I was _________by the question.
