Choose the letter A, B, C, or D to indicate the sentence which is the most correct.

I / ask/ they/ revise / every unit of their textbook.

Mai last time travelled to Europe two years ago.

It has been two years since Mai last travelled to Europe.

Mai haven't travelled to Europe for two years.

Mai began travelling to Europe two years ago.

I join the school English club, and work as a tutor of English.

I joined the school English club, and work as a tutor of English.

I joined the school English club, and worked as a tutor of English.

I join the school English club, and worked as a tutor of English.

Her little son has never tried Indian food before.

Her little son started to try Indian food when he was little.

Her little son first tried Indian food when he was little.

Her little son has tried Indian food since he was little.

An has started doing yoga since 6 o'clock.

It's 6 hours since An started doing yoga.

An has done yoga since 6 o'clock.

An has done yoga for 6 hours.

I tutored some primary school students for a semester.

I tutor some primary school students for a semester.

I have tutored some primary school students for a semester.

I tutoring some primary school students for a semester.

George and his friends has started to phone each other since last night.

Last night was the last time George and his friends have phoned each other.

Last night George and his friends didn't phone each other.

George and his friends last phoned each other last night.

At first, they can’t speak or write a full simple sentence.

At first, they couldn’t speak or write a full simple sentence.

At first, they don’t speak or write a full simple sentence.

At first, they didn’t can speak or write a full simple sentence.