$\text{ĐÁP ÁN+GIẢI THÍCH:}$

$\text{1. I'M LEAVING NOW BECAUSE I DON'T WANT TO MISS THE TRAIN}$

$\text{2. I HAVEN'T SEEN MY UNCLE FOR 2 YEARS}$

$\textit{bỏ WAS đổi AGO sang FOR}$

$\text{3. BECAUSE THE TRAFFIC LIGHTS TURNED RED, HE STOPPED THE CAR}$

$\text{4. THEY'VE NEVER BEEN TO THE KOREA BEFORE}$

$\textit{NEVER...BEFORE}$

$\text{5. WHEN DID YOU JOIN A MEMBER OF VOLUNTEERS IN ASIA ?}$

$\text{6. HE HAS CAREERED AS A TEACHER FOR 20 YEARS}$

$\textit{CAREER -> CAREERED}$

$\text{7. SCIENTISTS HAVE FOUGHT AGAINST AIDS SINCE 1980}$

$\textit{IN -> SINCE}$

$\text{8. BECAUSE THEY DO VOLUNTEER WORK, THEY LIKE DOING SOMETHING USEF}$

$\text{9. I WON'T BE ABLE TO ATTEND THE MEETING, BECAUSE I WILL BE ON HOLIDAY WITH MY FAMILY}$

$\text{10. SHE HASN'T NEVER WORKED WITH FOREIGNERS}$