Which of the sentences are grammatically correct? Choose the right option.

• My parents have just returned from Australia.
• He hasn’t finished reading the book about Steve Irwin yet.
• Have you ever heard the laugh of the kookaburra?
• He have never been to Australia.
• Mike for the first time has seen a kangaroo.
• Have you ever swim in the Pacific ocean?
• You have ever eaten a lamington?
• Captain James Cook has discovered Australia in 1770.