10. Food should be stored in a refrigerator at 5°C or below. It can remain fresh longer. (in order that).
->Food should be stored in a refrigerator at 5°C or below in order that it can remain fresh longer. 
11. Mark keeps eating junk foods. He is at high risk of obesity and type 2 diabetes. (even though).
->Even though Mark keeps eating junk foods, he is at high risk of obesity and type 2 diabetes.
12. Wendy and Joy totally concentrated on their work. The clock struck twelve. (until).
->Wendy and Joy totally concentrated on their wor until the clock struck twelve
13. Damian's parents felt very disappointed in him. His exam results were bad. (owing to).
->Damian's parents felt very disappointed in him owing to his bad exam results
14. She went to a French bakery. She wanted to buy some sandwiches and chocolate muffins. (so as to).
->She went to a French bakery so as to buy some sandwiches and chocolate muffins
15. I was driving at midnight. A black cat suddenly ran across the street. (while).
-> While I was driving at midnight, a black cat suddenly ran across the street.