Today I'm very happy because I got an excellent score on my math test. I used to be bad at math but now I'm trying as much as I can to improve it. And because I received a good score on my test, I really feel like my efforts have paid off.

They have the same meaning, and the nuance is near identical. Example: A: "There's been so many break-ins in the area recently, my friend's apartment was broken into! I'm getting really scared about it." B: "Your friend's was broken into? No way! A friend of mine had her apartment broken into too. I'm thinking of moving to a different neighbourhood to be honest..." If you wanted to use the two interchangeably you'd have to add emphasis on certain words to make it sound like you weren't just repeating what person A said. It's honestly so slight a difference, it's probably just for linguistic variance in a conversation so that people aren't just repeating what the person in conversation just said to them.

My name is Xin Xin. It sounds strange, but my parents usually call me this. In fact, I am called Zhuang Chuangxin. I’m 21 years old, of the Han nation, and I come from China. I live with my parents and brother. I also have a cute cat. I am a freshman at an ordinary university in Guangzhou. I have black eyes, short straight black hair, a big nose, and yellow skin. I’m short-sighted, so I need to wear glasses. I’m an introvert, so I don't really like talking with people. So, my favorite thing is reading books. I think books are my best friends, I feel it especially when I read science books such as The Easy History Of Time. I also like playing the video game Age of Empires III. Not only do I get happiness, but I also gain some knowledge of world history when I play it.

We went boating on the lake. Because you're physically on top of the lake. If you were boating in the lake that would give the image that the boat is sinking.