Hi Claire A few corrections: ‘Helen is thoughtful of me….’ Depending on what you are treying to say, there are 2 different ways of correcting the second sentence: “She bought a beautiful pair of sunglasses for me when she knew I needed them.” (she purchased them for me) Or “She brought a beautiful pair of sunglasses to me when she knew I needed them” (she gave them to me) instead of ‘a beautiful pair of sunglasses’, you could also use ‘some beautiful sunglasses’. Sunglasses is always plural.

" a beautiful sun glasses "is wrong Instead, a pair of beautiful sun glasses a pair of glasses 一副眼镜 you can't say "a glasses",what 's that?