In which of the following sentences is the underlined word a past participle?

None, apparently.

To answer this question, we need to understand what a past participle is.

A past participle is a verb form that is typically used to form verb tenses, such as the past perfect or the present perfect. It is formed by adding -ed, -d, -t, -en, or -n to the base form of a regular verb (e.g., walked, played) or as an irregular verb form (e.g., gone, taken).

Now, let's analyze each sentence to identify the underlined word that is a past participle:

1. She has **broken** her phone.

In this sentence, the underlined word "broken" is a past participle. It is derived from the base form "break" by adding -en, which is a common way to form past participles.

2. I am **eating** an apple.

In this sentence, the underlined word "eating" is NOT a past participle. It is a present participle, which is formed by adding -ing to the base form of a verb.

3. The movie was **directed** by a famous director.

In this sentence, the underlined word "directed" is a past participle. It is derived from the base form "direct" by adding -ed.

4. They have **chosen** a new leader.

In this sentence, the underlined word "chosen" is a past participle. It is derived from the base form "choose" by adding -en, which is another way to form past participles.

Therefore, the sentences in which the underlined word is a past participle are:

- She has **broken** her phone.
- The movie was **directed** by a famous director.
- They have **chosen** a new leader.