Complete the sentences. Use the present perfect of the verbs in brackets: 1. These plates are clean. Katya ___ ___ them. (wash) 2. The armchair is next to the sofa. We___ ___it. (move) 3. The girls are not here. They ___ ___ yet. (not come) 4. ___ you ___ him today? (see) 5. Why __ mum ___ the door? (lock)

1. These plates are clean. Katya has washed them.
Explanation: The action of washing the plates happened in the past, but it has a connection to the present because the plates are currently clean. We use the present perfect tense to express an action that happened in the past but has a relevance to the present.

2. The armchair is next to the sofa. We have moved it.
Explanation: The action of moving the armchair happened in the past, but it has a connection to the present because the current location of the armchair is next to the sofa. We use the present perfect tense to express an action that happened in the past but has a relevance to the present.

3. The girls are not here. They have not come yet.
Explanation: The action of coming has not happened yet. The girls were expected to be here, but they haven't arrived. We use the present perfect tense to express an action that started in the past and has a relevance to the present (the present result is that they are not here).

4. Have you seen him today?
Explanation: The question is asking about an action of seeing that happened at some point before now (today). The present perfect tense is used because the action is connected to the present (today).

5. Why has mum locked the door?
Explanation: The question is asking about the reason behind the action of locking the door. The present perfect tense is used because the action of locking the door happened in the past, but it has a relevance to the present (the door is currently locked).