e used to do sth.被用来做某事
e.g.Telephones are used to communicate with others.
be used as … 被用来当做
e.g.Telephones are used as communicating tools.
e used to do sth.被用来做某事
e.g.Telephones are used to communicate with others.
be used as … 被用来当做
e.g.Telephones are used as communicating tools.