A. Modal Particles:

There are some modal particles used at the end of the sentences or following verbs. They colloquially indicate kinds of moods or emotional colors of sentences and they are all used in soft tones without any tone marks.

1. “了” is used to emphasize the accomplishment of an action and the sentence with this action.
e.g. Wǒ yǐjīng xué le sān nián Zhōngwén le. 我已经学了三年中文了。(I have already learned Chinese for three years. )

2. “吗” is used at the end of an interrogative sentence which has been transferred from an affirmative sentence. It cannot be used in an alternative question.
e.g.
Nǐ chī fàn le. 你吃饭了。(You have eaten.)
Nǐ chī fàn le ma? 你吃饭了吗？(Have you eaten yet?)
But:
(wrong) 你吃不(bù)吃饭吗？(right) 你吃不吃饭呢？(Do you want to eat or not?)

“吗” is also used in a rhetorical sentence which does not need to reply.
e.g ：
你不想学中文吗？(Don’t you want to learn Chinese?)

3. “么” can be replaced “吗”, but it is not as formal as the latter.

4. “呢” is used in an alternative question or a question with interrogative words.
e.g.
她会不会讲汉语呢？(Can she speak Chinese or not?)
谁是我们的中文老师呢？(Who is our Chinese teacher?)

Some special points different from English:

1. A quantifier should be used between a number and a noun.

liǎng zhī lǎohǔ 两只老虎 (two tigers)
shí zhāng yǐzi 十张椅子 (ten chairs)

but nouns with “们 ” cannot go with numbers:
e.g. háizǐmén 孩子们 ( children, kids ) , Wrong : 三个孩子们

2. Tenses are not expressed by the verbs themselves but by the adverbials of time or the model particles:

gāngcái wǒ chūqù le . 刚才我出去了。(I just went out.)

3. There are no cases changed for the personal pronouns :

Tā jiào wǒmén guǎn hǎo wǒmén zìjǐde shì. 他叫我们管好我们自己的事。(He asked us to mind our own business.)

4. Adverbials of time are put before the predicate verbs:

Wǒmén jīntiān xiàwǔ qù le sènghéxī. 我们今天下午去了圣荷西。 (We went to San Jose this afternoon.)

5．The orders of array are different. From big to small, and from time to location:

e.g 2007 nián bā yuè bā rì shàngwǔ shídiǎn zài jiùjīshān liánhé guǎngchǎng 2007年八月八日 上午十点 在旧金山联合广场
(at the Union Square of San Francisco on August 8th, 2007)

6. The order of a question is different:

a) Nín shì lǎoshī. 您是老师。
Nín shì lǎoshī ma? 您是老师吗？— to change an affirmative sentence into a question by adding a “吗 ” and “?” at the end of the sentence. (Are you a teacher?)

b) Tāmén de lǎoshī shì shuí ? 他们的老师是谁？
Shuí shì tāmén de lǎoshī ? 谁是他们的老师？— interrogative words can be put in an ambulatory place of a sentence. (Who is their teacher?)