Pronoun reference and omission: 他, 它, 这, 那
【五70】【五71】句群 / sentence groups
Tone colorsā tone 1á tone 2ǎ tone 3à tone 4a neutral
To hold a paragraph together, Chinese picks the subject up again with a pronoun or does not repeat it at all. 他 / 她 for a person, 它 for a thing, an animal or a city, 这 / 那 / 这里 / 那里 for a place or for the whole idea just stated: 重庆是一座建在山上的城市。它的夜景很有名。
When the subject stays the same from one clause to the next and the reader can recover it, you drop it: 我是法国人，在成都留学三年了，很喜欢这里. Only the first 我 is written. Where French and English say "I" before every verb, Chinese lets the verbs run on. The dropped subject can even be the object of the previous clause: 爸爸妈妈来送我，带着水果上了火车 (it is "I" who board the train).
Don't repeat the same noun at the start of every sentence either (这个小伙子是留学生。这个小伙子在英国学过中文 is heavy): 他 lightens it. But if two people are involved, keep the name, or 他 becomes ambiguous. This device belongs to the text (句群: a group of sentences) more than to the single sentence: it matters most when you write.
Examples
我是法国人，在成都留学三年了，很喜欢这里。
Wǒ shì Fǎguórén, zài Chéngdū liúxué sān nián le, hěn xǐhuan zhèlǐ.I'm French, have been studying in Chengdu for three years and really like it here.
重庆是一座建在山上的城市。它的夜景很有名。
Chóngqìng shì yí zuò jiàn zài shān shang de chéngshì. Tā de yèjǐng hěn yǒumíng.Chongqing is a city built on hills. Its night views are famous.
小唐是我的同学。他从小在成都长大，最爱吃那里的小吃。
Xiǎo Táng shì wǒ de tóngxué. Tā cóngxiǎo zài Chéngdū zhǎngdà, zuì ài chī nàlǐ de xiǎochī.Xiao Tang is my classmate. He grew up in Chengdu and loves the street snacks there.
离开家乡的那一天，爸爸妈妈都来车站送我，带着他们准备的水果上了火车。
Líkāi jiāxiāng de nà yì tiān, bàba māma dōu lái chēzhàn sòng wǒ, dài zhe tāmen zhǔnbèi de shuǐguǒ shàng le huǒchē.On the day I left my hometown, my parents all came to the station to see me off, and I boarded the train with the fruit they had prepared.
这家公司在重庆，那家在成都。这就是我犹豫的原因。
Zhè jiā gōngsī zài Chóngqìng, nà jiā zài Chéngdū. Zhè jiù shì wǒ yóuyù de yuányīn.This company is in Chongqing, the other in Chengdu. That is exactly why I'm hesitating.
Common mistakes
✗ 我决定出国留学，我不得不和父母告别，我心里有些担心 → ✓ 我决定出国留学，不得不和父母告别，心里有些担心 (the subject is written once, the following "I"s stay silent).
✗ 这个小伙子是留学生。这个小伙子在英国学过中文。 → ✓ 这个小伙子是留学生。他在英国学过中文。 (pick up with a pronoun).
✗ 小唐和雷米去了成都。他很喜欢那里。 → 他 is ambiguous when two people are involved: repeat the name.