1） 大部分形容词加-ly可构成副词。但 friendly，deadly，lovely，lonely，likely，lively，ugly，brotherly，仍为形容词。
改错：(错） She sang lovely.
（错） He spoke to me very friendly.
（对） Her singing was lovely.
（对） He spoke to me in a very friendly way.
 
2）有些以-ly 结尾既为形容词，也为副词。
daily，weekly，monthly，yearly，early
The Times is a daily paper.
The Times is published daily.