Hi, for the verb "to visit", you can use 拜訪 or 參觀. The meaning doesn't vary that much, but there's a slight difference while applying them.
eg. I'll visit my friend's house on Sunday. 我禮拜(星期)天要去拜訪我朋友家。
Have you visited the museum yet? 你去參觀過美術館了嗎?
btw, we say to visit “中文”怎麼說, not 中國 (that's the name of country). But nice try!;)
And, 大姐 is like the boss, the head leader in a particular group. People kind of pay respect to them due to their social status and power over many things; 大哥 likewise. But we also use it as eldest sister, to call your siblings or sister in law..etc. For example, my mom calls my dad's older sister 大姐:)
Keep it up! and 再見!