In the supermarket you would also find many frozen foods --- frozen fruits, vegetables, me

In the supermarket you would also find many frozen foods --- frozen fruits, vegetables, meat and fish. As techniques for 5. (freeze) food are being improved, more frozen foods are appearing on the market, and more people are buying them. Fruits and vegetable to be sold in the supermarket are often frozen the moment 6. are picked. The 7. fruits and vegetable are frozen, the better.8. machines are often taken into the fields where9. food grows, so that little time is lost 10. picking and freezing.1. to kill 2.unsafe 3. if / when 4.who 5. freezing

(答案→)1. to kill 2.unsafe 3. if / when 4.who 5. freezing 解析：无

就是这个解释