喂。 Hello!
您好。 Hello!

Explain:
喂 hello
您 you
好 good
Notes:
“喂。” and “您好。” both means “ Hello!” They are common Chinese telephone phrases, and frequently used to answer a telephone or start a telephone conversation.

请问您找谁？
Whom do you want (to speak to)?
Explain:
请问 may I ask
您 you
找 speak to/look for
谁 who
Notes:
“请问您找谁？” means “Whom do you want (to speak to)?” This is a daily Chinese telephone phrase. It is often used in the situation that the speaker doesn’t know who is calling when beginning a telephone conversation.

请问哪位？
May I ask who is calling?
Explain:
请问 may I ask
哪位 who
Notes:
“请问哪位？” means “May I ask who is calling?” This is a common Chinese phrase used when the speaker wonders who's calling on the telephone.

杰克在吗？
Is Jack in?
Explain:
杰克 Jack
在 in
吗 (a particle used at the end of questions)
Notes:
“杰克在吗？” means “Is Jack in?” This sentence is used to answer the preceding question, “请问您找谁？” It can also be used when you visit a friend and the person who answers the door is riot the one you want.

你打错了。
You have dialed the wrong number.
Explain:
你 you
打错 dialed the wrong number
了 (past tense marker)
Notes：
“你打错了。” means “You have dialed the wrong number.” This is a common telephone phrase when you get a strange call from someone you don't know.

我就是。
This is …speaking.
Explain:
我 I
就 just
是 am/ is/ are
Notes:
“我就是。”means "This is … speaking." When someone wants you on the phone and you are answering it, you may say this to the speaker. And it can also be used when someone you never meet before comes for you.

您过会儿再打吧。
You could ring back later.
Explain:
过会儿 later/ a moment
再 again
打 dial
吧 [(used at the end of a sentence) indicating entreaty, suggestion, command, etc.]
Notes:
“您过会儿再打吧。” means “You could ring back later.” It is used in the situation of giving someone a suggestion on the phone when the person he wants to speak to is not in but will be back soon.

他出去了。He’s out
他不在家。 He’s not at home.
Explain:
他 he
出去 out
不在 not in
家 home
Notes:
“他出去了。” and “他不在家。” mean “He’s out/ not in.” They are common telephone phrases. Please notice “他” in this sentence, which can be replaced by many names.

你要留话吗？
Would you like to leave a message?
Explain:
你 you
要 want
留话 leave a message
吗 (a particle used at the end of questions)
Notes:
“你要留话吗？” means "Would you like to leave a message?" You may use this phrase to suggest someone on the telephone when the person he wants to talk to goes out or is not at home? and you would like to help him take a massage.

您稍等。
Wait a minute. / Hold on please.
Explain:
您 you
稍等 wait a minute
Notes:
“您稍等。” means “Wait a minute. / Hold on please.” This is polite way of asking someone on the telephone to wait until the person whom he wants to talk to is available and you'll help to find him/her.