absorb sb in doing
sb in doing sth
absorb oneself in
sb should be doing in doing
sb have trouble (in) doing
join sb in doing还是join sb doing
absorb
sb spend some time in doing sth
join sb in doing sth 是什么意思?
sb.spend time(in)doing sth.
sb spend time mony in doing sth
help sb in doing sth &help sb to do sth
assist sb in doing sth中in可否省略?