Answer:
They try their best to patch it up and begin to fight off the sharks with an oar.
Explanation:

Search engines work by crawling hundreds of billions of pages using their own web crawlers. These web crawlers are commonly referred to as search engine bots or spiders. A search engine navigates the web by downloading web pages and following links on these pages to discover new pages that have been made available
Predicate adjective and direct object
Answer:
The tour guide, who has become a good friend, is great!
Explanation:
The commas help separate the two ideas in one sentence correctly. A good way to check that this is correct is to remove the words separated by the commas - "who has become a good friend" - and check if the sentence still makes sense. In this case it would be "The tour guide is great!" which makes sense as a sentence. Thus, this version of the sentence is correct.