句子成分之謂語

謂語
謂語（predicate verb）是對(duì)主語動(dòng)作或狀態(tài)的陳述或說明，指出“做什么”、“是什么”或“怎么樣”。謂語動(dòng)詞的位置一般在主語之后。
謂語由動(dòng)詞充當(dāng)，說明主語所作的動(dòng)作或具有的特征和狀態(tài)。依據(jù)其在句中繁簡(jiǎn)程度可把謂語分為簡(jiǎn)單謂語和復(fù)合謂語兩類。不論何種時(shí)態(tài)、語態(tài)、語氣，凡由一個(gè)動(dòng)詞（或動(dòng)詞詞組）構(gòu)成的謂語都是簡(jiǎn)單謂語。

簡(jiǎn)單謂語：
由動(dòng)詞、動(dòng)詞短語或者動(dòng)詞的時(shí)態(tài)構(gòu)成。如：
I like walking. (一般現(xiàn)在時(shí)主動(dòng)語態(tài))

I made your birthday cake last night. (一般過去時(shí)主動(dòng)語態(tài))

It is used by travellers and business people all over the world. (一般現(xiàn)在時(shí)被動(dòng)語態(tài))

復(fù)合謂語：
1.由情態(tài)動(dòng)詞或助動(dòng)詞+不帶to的動(dòng)詞不定式構(gòu)成。如：
You may keep the book for two weeks.
He has caught a bad cold.
My sister is crying over there.
I have been waiting for you all the time.
I would stay at home all day.

2.由系動(dòng)詞加表語構(gòu)成。系動(dòng)詞不能單獨(dú)作謂語，要和表語一起作謂語。
We are students.
Your idea sounds great.