英语语言学题，会的学姐学长帮帮忙啦

LX林夕梦

可以写出解释吗

来自Android客户端

LX林夕梦

structure Analysis
state whether each of the underlined constructions or word groups is headed or non-headed. IF headed state its headed word name the type of constructions
1. Ducks quack
2. His handsome face appeared in the magazine.
3. The ladder in the shed is long enough.
4. she is pretty optimistic about the future.

来自Android客户端