The sentences provided are correctly completed with the present perfect tense that describes actions occurring at an unspecified time in the past or continuing into the present. The auxiliary verbs 'have/has' are used with the past participle of the main verb to construct these sentences.
Step-by-step explanation:
The student is working on an exercise related to verb tenses, specifically, the present perfect tense. This tense is used to describe actions that have happened at an unspecified time in the past or started in the past and continue in the present. The structure of the present perfect tense is 'have/has' plus the past participle of the main verb.
Here are the sentences completed with the correct form of the verbs in brackets:
- At last! I have solved the problem.
- What have you done recently? Anything interesting?
- My brother has bought a new motorbike. It looks great.
- Have you swum? Your hair looks wet.
- Oh, There you are! I have been looking for you everywhere.
- Sorry we are late. How long have you been waiting?
- I have known Peter for a long time.
- My friends have been running for two hours already.
- I have never understood Maths and Physics.
- The children are tired because they have been playing all day.
- Susan has never believed in ghosts and fairies.
- I have been writing emails all day.
- John has never seen this film before.
- What on earth have you been doing? You're covered in mud.
- Have you ever seen Altamira Cave? I hear it's incredibly beautiful.
- How long has he been learning English?
- I have just spoken to my cousins. They told me the news.