卧底
to work undercover; to engage in clandestine intelligence gathering; to act as a planted agent
In context
Time & aspect: general patterns
The form of 卧底 does not change for “I”, “you”, past or future. These comparison examples use 学习 (study), 吃 (eat) and 开 (open) to show how Mandarin expresses time and aspect. They are general models, not forms of 卧底.
Mandarin uses time expressions and context for when, and aspect markers for how an event or state unfolds. There is no single set of verb endings equivalent to all English tenses.
The pattern must fit the meaning of 卧底. Some verbs describe states, brief events or special constructions, so the markers below are not interchangeable additions.
Present & habitual
Time or frequency + verb
Context can describe the present or a routine. A word such as 每天 makes the repeated time clear; the verb keeps the same form.
我每天学习中文。
I study Chinese every day.
Past time
Past time expression + verb
A past time expression can locate a situation without a past-tense ending. 了 is not required in every sentence about the past.
去年我在北京学习。
Last year I studied in Beijing.
Future & plans
Future time + intention or prediction
A future time word can establish when something will happen. 打算 expresses a plan; 会 can express a prediction. They are not universal future-tense endings.
明天我打算学习中文。
I plan to study Chinese tomorrow.
Completed event · 了
Verb + 了 + object
了 can present an event as realized or bounded. To say that a task is finished, a result word such as 完 may also be needed. 了 does not simply mean “past”.
我吃了一个苹果。
I ate an apple.
Past experience · 过
Verb + 过 + object
过 marks having had an experience before. It does not function like every English “have + past participle” construction.
我吃过这个菜。
I have tried this dish before.
Action in progress · 正在
Subject + 正在 + action
正在 places you in the middle of an activity. A past or future time expression can move that viewpoint to another time. Ordinary possession and other states need a different pattern.
我正在学习中文。
I am studying Chinese right now.
Continuing state · 着
Suitable verb + 着
着 can describe a state that continues, such as a door remaining open. It is not interchangeable with 正在 and does not fit every verb.
教室的门开着。
The classroom door is open.
New situation · 了
New situation + sentence-final 了
Sentence-final 了 can signal that the situation is different now. This use can describe a present change rather than a past event.
我现在不吃肉了。
I no longer eat meat.
Negative statements
不 or 没(有), according to meaning
不 often denies a habit or intention. 没(有) can deny that an event happened; completed-event 了 is normally removed. To deny possession, 有 becomes 没有.
我不吃肉。
I do not eat meat.
我昨天没吃早饭。
I did not eat breakfast yesterday.
Continue with 了, 过, or actions in progress.
Grammar references & example notes
These are original teaching examples. Pinyin shows common spoken tone changes for 一 and 不; third-tone combinations keep their dictionary marks. The guide covers common contrasts, not every construction or every sense of a verb.
Try to recall it
Recall the verb meaning “to work undercover; to engage in clandestine intelligence gathering; to act as a planted agent”. Type its simplified characters without looking at the heading.
Meaning and word pinyin adapted from Wiktionary contributors via Kaikki. In-context examples are adapted from the same dictionary entry. Time-and-aspect examples are original teaching material. Dictionary adaptations and original teaching examples are available under CC BY-SA 4.0. Simplified script and display formatting may be normalized. Data and review notes.