How +形容词+ a +名词+陈述语序　How+形容词或副词+陈述语序What +名词+陈述语序What+a+形容词+名词+陈述语序What+ 形容词+复数名词+陈述语序What+ 形容词+不可数名词+陈述语序How clever a boy he is!How lovely the baby is!What noise they are making!What a clever boy he is!What wonderful ideas (we have)!What cold weather it is!感叹句的省略形式为：What a clever boy (he is)!