The ba sentence and the bei passive 把字句与被字句

✗ 我把喜欢中国菜。把 cannot attach to 喜欢, a mental/static verb — there is nothing being disposed of or changed. ✓ 我喜欢中国菜。(Wǒ xǐhuan Zhōngguó cài.) — I like Chinese food. Verbs like 是, 有, 喜欢, 知道 and 姓 describe a state, not an action on an object, so they never appear in a 把 sentence.

✗ 我把一个苹果吃完了。一个苹果 is "an apple", not a specific, already-known one, so 把 cannot be used. ✓ 我把那个苹果吃完了。(Wǒ bǎ nàge píngguǒ chī wán le.) — I finished eating that apple. If the object is not identifiable to the listener, drop 把 and use a plain sentence: 我吃了一个苹果。(Wǒ chī le yí ge píngguǒ.) — I ate an apple.

✗ 我把作业做。The verb 做 stands alone — a 把 sentence needs a complement after the verb. ✓ 我把作业做完了。(Wǒ bǎ zuòyè zuò wán le.) — I finished the homework. After 把, the verb must be followed by a result, direction or place complement (做完, 拿过来, 放在桌子上); a bare verb is always incomplete.

✗ 我把作业做了完。了 has been inserted between the verb 做 and its complement 完. ✓ 我把作业做完了。(Wǒ bǎ zuòyè zuò wán le.) — I finished the homework. 了 must come AFTER the whole verb + complement unit (做完了), never in the middle of it. This is the same misplaced-了 error the examiner reports flag repeatedly.

✗ 我被吃了那个苹果。This calques "the apple was eaten by me", but 被's subject must be the RECEIVER, not the eater. ✓ 那个苹果被我吃了。(Nàge píngguǒ bèi wǒ chī le.) — That apple was eaten by me. In a 被 sentence the thing something happens TO comes first, then 被, then the agent.

✗ 我的作业被我把弄丢了。Both 把 and 被 mark the same verb — that is ungrammatical, so choose ONE. ✓ 我把作业弄丢了。(Wǒ bǎ zuòyè nòng diū le.) — I lost the homework. OR 我的作业被弄丢了。(Wǒ de zuòyè bèi nòng diū le.) — My homework got lost. Use 把 to keep the agent as subject, 被 to make the receiver the subject — never both at once.

把 is not decorative word order — it is grammatical only when the object is SPECIFIC and the verb carries a result, direction or place complement, and it cannot be used with static/mental verbs at all. ✗ 我把喜欢中国菜。(把 cannot attach to 喜欢) ✓ 我喜欢中国菜。(Wǒ xǐhuan Zhōngguó cài.) — I like Chinese food. 把 changes what a sentence can grammatically do, not just its word order.

Many ideas that are passive in English are more natural stated ACTIVELY in Chinese, especially when the agent is obvious. 被 is reserved mainly for foregrounding the receiver — often because something unwelcome happened. "The window was opened (by me)" is usually just 我打开了窗户。(Wǒ dǎkāi le chuānghu.), while "My phone was broken by my brother" naturally takes 被: 我的手机被弟弟弄坏了。