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.

道岔表示器的显示方式有哪些？