each什么意思,each

i wonder if we ever think of each other at the same time.
不定代词both_all_neither_either_none_any_eachppt
walking distance是什么意思?口中怎么用?
eachline方法也是支持1个或2个参数的,这两个参数分别是什么意思,就
"one period each week" 是什么意思?