STUDENT: About my sister...

CORRECT: About my sister:

EXPLANATION:

a. Ellipsis [...] is used to express an incomplete thought. On the other hand, colon [:] is used to say that you are still to give details to the previous sentence.

STUDENT: My sister's name is Hwang hyun jung.

CORRECT: My sister's name is Hwang Hyun Jung.

EXPLANATION:

a. When writing a name, the first letter should always be capitalized.

STUDENT: Her English name is Grace. She is studying in TalkFun too.

CORRECT!

STUDENT: She is 17years old. She is in the first grade in high school.

CORRECT!

STUDENT: she is always busy.because, she has to study in school untill 10:00pm.

CORRECT: She is always busy. because, she has to study in school untill 10:00pm.

EXPLANATION:

a. As much as possible, do not begin a sentence with conjunctions such as "because", "but" "and" etc.

STUDENT: So sometimes she is annoyed. When she is annoyed , We fight.

CORRECT: So sometimes she is annoyed. When she is annoyed , we fight.

EXPLANATION:

a. We do not capitalize the first letter of the word after a comma.

STUDENT: But she is kind. I like her.

ACCEPTABLE, BUT AS MUCH AS POSSIBLE, DO NOT START A SENTENCE WITH A CONJUNCTION.

Emily, believe it or not, I have taught your sister a year ago. So basically, I know Grace. It's just that I could not remember her face anymore.