My favorite book these days is a series of “(or more precisely, book series) is the Oxford Bookworm” that series. I’ve been starreading to readhat to sturdy English for about eight months.

I can learn about many things that I have never known, likeThanks to that book series, I can learn about many previously unknown things such technology or historical figures.

My favorite book these days is a series of “Oxford Bookworm” that I’ve been starting to read in order to sturdy English for about eight months.

“Starting” is the correct verb here because it means to begin an activity. “Staring” means to look at something for a long time, which doesn’t fit the context of beginning to read.
“Study” means to learn, which fits the context of learning English. “Sturdy” means strong, which is unrelated to the context.

I can learn about many things that I ha’ve never known, like technology or historical figures.

“I can learn many things” instead of “I can learn about many things”: “About” is not necessary here. “I can learn many things” is more concise and sounds more natural.
“Many things” makes more sense in this context than “things about,” as you’re referring to gaining new knowledge, not just “about” something.

My favorite book these days is athe series of “Oxford Bookworm” that I’ve been staringted to read to sturdy English forsince about eight months ago.

My favorite book these days is a series of “Oxford Bookworm” that I’ve been starting to read to sturdy English for about eight months.

staring? (to look at) or starting? (to begin, to start)

My favorite book these days is athe series of “Oxford Bookworm.” that I’ve been staring to readreading it to sturdy English for about eight months.

You can start to do something, but you can’t start to do something for a period of time. Instead of saying “I’ve been starting to read it to study English for about eight months”, just say “I’ve been reading it to study English for about eight months.”

I canhave learned about many things that I have never knownew, like technology or historical figures.

Phrasing it this way makes it sound better with the verb tense in the previous sentence.