$1.$ Andrew will go to Sa Pa because he likes mountain climbing.

$-$ Câu thứ $2$ về Andrew: "He likes mountain climbing. He'll go to Sa Pa".

$2.$ Jane has visited Viet Nam twice. She'll go to Ha Long Bay.

$-$ Câu thứ $1 & 2$ và câu thứ $3$ về Jane: "Jane likes swimming and sunbathing. She has been to VN twice and she has already visited Nha Trang. She'll go to Ha Long Bay"

$3.$ Mary can find an oceanic institute in Nha Trang.

$-$ Câu thứ $2$ và câu thứ $3$ về Mary: "She also wants to visit an oceanic institute in VN. She'll go to Nha Trang".

$4.$ Mary wants to travel by train because she wants to see as much of the country as possible.

$-$ Câu thứ $1$ về Mary: "Mary loves VietNam and she wants to travel by train to see as much of the country as possible".

$5.$ Donna has a flower shop in Los Angeles.

$-$ Câu thứ $1 + 2$ về Donna: "Donna loves flowers. She has a flower shop in Los Angeles".

$6.$ In Viet Nam, we can find beautiful flowers in Da Lat.

$-$ "She is thinking of importing flowers from VN. She'll go to Da Lat".

`1`. Because he likes mountain climbing.

`-` Dẫn chứng: dòng `1` 

`2`. Jane has been to VN twice. She will go to Ha Long Bay.

`-` Dẫn chứng: dòng `6+ 7`

`3`. Mary can find an oceanic institute in Nha Trang.

`-` Dẫn chứng: dòng `2+ 3`

`4`. Because she wants to see as much of the country as possible.

`-` Dẫn chứng: dòng `2`

`5`. She has a flower shop in Los Angeles.

`-` Dẫn chứng: dòng `8`

`6`. We can find beautiful flowers in Da Lat.

`-` Dẫn chứng: dòng `8+ 9`