Sind die Sätze richtig in present perfect?
Ich möchte gerne wissen ob ich für den Grammatikteil meiner Klassenarbeit gut vorbereitet bin (:
1.Tim has already written ten e-mails to the oil companies
2. They haven't answered yet.
3. Why have so many trees disappeared?
4. The price of oil have increased since April.
5. We have heard about the companies plan to build a new pipeline.
6. It haven't rained for weeks.