A few questions.
1.Not only he but also his friends (have/has) the ability to speak another language. (Have or has?)

2.They took my pictures/They took pictures of me. (What's the difference?)

3.As is known to all that..... .(Is this correct structure?)

4.The Cutty Sark was one of the fastest sailing ships that has/have ever been built. (has or have?)

Question

A few questions.
1.Not only he but also his friends (have/has) the ability to speak another language.         (Have or has?)

2.They took my pictures/They took pictures of me.     (What's the difference?)

3.As is known to all that.....    .(Is this correct structure?)

4.The Cutty Sark was one of the fastest sailing ships that has/have ever been built.       (has or have?)

Answer

1. have - You conjugate it with "friends". Say it another way, to check: His friends have the ability to speak another language, just like he does.
2a. "They took my pictures." can mean they got, accepted, or stole your photos.
2b. "They took pictures of me." usually means they snapped some photos of you.
3. Hard to tell. Sorry.
4. have - You conjugate it with "ships". Another way to say it: Of sailing ships that have ever been built, the Cutty Sark was one of the fastest.