There are three main types of Mandarin verbs - Stative Verbs, Activity Verbs, and Achievement Verbs. Stative verbs describe a relatively unchanging state, while activity and achievement verbs are used for actions or activities.
Examples Of Activity Verbs

Mandarin activity verbs include:

    吃 - chī - to eat
    喝 - hē - to drink
    看 - kàn - to see
    說 / 说 - shuō - to talk
    買 / 买 - mǎi - to buy

Activity verbs are defined as actions which have duration. This distinguishes them from stative verbs and achievement verbs, which have no duration.

Duration Of Activity Verbs

All activity verbs can take place over a period of time, which we can specify with expressions such as the verb suffix 着 (zhe - indicating an on-going action), or 正 (zhèng) and 正在 (zhèngzài), both of which indicate that the action is occurring at the present moment.

The verb suffix 了 (le) can be used with activity verbs to show that the action occurred in the past. A time duration can be used with the 了 (le) suffix, as in the following example:

    他念書念了一個鐘頭。
    他念书念了一个钟头。
    Tā niànshū niàn le yīgè zhōngtóu.
    He studied for one hour.

Direct Objects With Activity Verbs

Most activity verbs have direct objects, as seen in the example above, wher the direct object of 念 (niàn - to study) is 書/书 (shū - book).

Some activity verbs have default direct objects, which are always used if there is no other direct object. Examples of default direct objects include:

    念書 / 念书 - niànshū - to study (books)
    吃飯 / 吃饭 - chīfàn - to eat (rice)
    說話 / 说话 - shuō huà - to speak (words)

Most of these default direct objects are not translated into English.