请问你哪里找？
May I ask who is calling?

我想拨国际长途电话。 
I'd like to make an overseas phone call.

我想拨对方付费电话。 
I'd like to make a collect phone call.

我等会儿再拨。 
I'll call back later.

恐怕您拨错电话号码。 
I'm afraid you have the wrong number.

 他/她什么时候回来？ 
When will he/her be back?

我想要留个话。 
I'd like to leave a message.