йʱķᴴɵҾҽƹЧȪˮ. ͬ˲ӱ. ֹͣǰʱ, ԭٶȻƶ򹥻еĲӸ.

֮Ȫ޷ݻ. , Ҫע, зӵ, ֮Ȫڵз, һƵз. ֮Ȫܻ.

Ҫٻ֮Ȫ,  [֮Ȫ] ͼʾϰ, ȻҪõĵصϰ. õ<link="topic:line of sight">Ұ</link>, ſҳ, ҪйĿռ.
