1. I am so pleased that I passed my English test. (replace "however" with "that")
2. I was really disappointed when I failed my history presentation. (replace "then" with "when")
3. Linda wants to buy a new large pink handbag. (no mistake)
4. I want to study abroad. Although, it is very expensive. (remove the comma after "although")

Corrected sentences:

1. I am so pleased that I passed my English test.
2. I was really disappointed when I failed my history presentation.
3. Linda wants to buy a new large pink handbag.
4. I want to study abroad. Although it is very expensive.