1. How
adj. (Subj. + be ) How lovely !
adv. (Subj. + v.) How well you sing !
subj. +v. How you work !
adj. + a (an) + n. How good a map it is!
2.What
a (an) (+ adj.) + n. What a rude man !
(+ adj.) + n. (可数名词复数） What lovely flowers !
( + adj.) + n. (不可数名词） What fine weather !
