Present Perfect Simple And Present Perfect Continuous

Explanation
The correct answer is "I've finished my homework. Now I'm going to watch TV." This sentence is correct because it uses the simple past tense "I've finished" to indicate that the homework is completed, and the present tense "Now I'm going" to indicate the current action of watching TV. The second sentence "I've been finishing my homework. Now I'm going to watch TV" is incorrect because it uses the present perfect continuous tense "I've been finishing" which implies that the action of finishing the homework is still ongoing, which contradicts the statement that the homework is already finished.

Explanation
The correct sentence is "What have you done with my keys? - I haven't seen your keys." This sentence is correct because it uses the past participle "done" to ask about a completed action of doing something with the keys. The response "I haven't seen your keys" indicates that the speaker has not seen the keys after the action was done.

Explanation
The correct answer is "She's been working in the garden all morning and she's still not finished." This sentence uses the present perfect continuous tense to indicate an action that started in the past, has been ongoing, and is still continuing in the present. It implies that the person is still working in the garden at the time of speaking. The second sentence, "She's worked in the garden all morning and she's still not finished," uses the present perfect tense, which suggests a completed action in the past with a present result. However, this doesn't convey the ongoing nature of the person's work in the garden.

Explanation
The correct answer is "What have you been doing? You're all wet." This sentence is correct because it uses the present perfect continuous tense ("have been doing") to ask about an action that started in the past and is still happening or has just finished. The use of "been doing" implies that the person has been engaging in an activity that has caused them to become wet.