So I watched a movie, in this sentence why did they use 吃 rather than 喝?
The character 吃 is also a variant of 喫 (same pronunciation), where it retains the meaning of both "to eat" and "to drink".
This usage is preserved for example in Shanghainese, where 吃 is commonly used with liquids, whereas 喝 instead is almost never heard:
(吴语）吃茶 (qiek4 zo1), 吃汤 (qiek4 tong1), 吃酒 (qiek4 jieu2), etc.
To complete @Lionel Rowe's answer, a common variant in traditional Chinese would be 喫茶 in lieu of 吃茶. 喫 can be replaced by 吃 safely, but the converse is not true. Furthermore, you can observe that the variant 喫茶 was imported in Japanese as well. Remarkably, there is a famous koan "喫茶去" from 趙州從諗 (you can read a rather complete translation of the story in 知乎).
In ancient China, there was still lees in wine, so say "eat". In modern, wine is pure liquid, so we say "drinking".
In ancient Chinese, we always say
吃酒 long long ago. So
吃 means drink. It's just a habit. So in some acient dramas like 三国演义Romance of the Three Kingdoms, 水浒传Water Margin, 红楼梦Dream of the Red Chamber, they always use
Now as times goes, we Chinese usually say
喝酒, rahter than
吃酒. For example, 嗨哥们，下班一块喝酒去. They will reponse with fine. But if you say 嗨哥们，下班一块吃酒去. Then they may say
既然敬酒不吃那就吃罚酒 actually is 敬酒不吃吃罚酒, which is usually seen or heard in certain contexts. For example, TV show or movie. this sentence shows very strong emotion(mostly is anger),so please use it carefully.
there is an interest example about 喝水 and 吃水
喝水, as you know, means drink water, but 吃水 have very different meanings.
a. Draft, the depth of water needed for a boat to be able to float.
b. coolant leaks into your car or motorcycle engine. (Taiwan)