a.

1. 活跃的；活泼的
   Mrs. Brown is over 80 and not very active now.

   布朗太太已八十多岁，现在不大活动了。

2. 积极的；勤奋的
   He became an active social reformer.

   他成了一位积极的社会改革家。

3. 在活动中的；在进展中的
   Mount Vesuvius is an active volcano.

   维苏威是一座活火山。

4. 现役的
5. 现行的，有效的
   an active law

   现行法律

6. 【语】主动的[Z]
   the active voice

   主动语态

n.

1. 积极分子[C]
2. 【语】主动语态[U]

adj.

1. moving or tending to move about vigorously or frequently.
   ▸(of a person's mind or imagination) alert and lively.
2. participating in a particular sphere or activity.
3. working or in operation.
4. Grammar  denoting a voice of verbs in which the subject is typically the person or thing performing the action and which can take a direct object (e.g. she loved him as opposed to he was loved). The opposite of passive.
5. (of a volcano) erupting or having erupted in historical times.
6. (of a disease) not in remission or latent.
7. having a chemical or biological effect on something.
8. (of an electric circuit) capable of modifying its state or characteristics automatically in response to input or feedback.

n.