四、请认真阅读下面短文，从短文后所给的六个选项中选出五个可以填入空白处的最佳选项。
〔人与社会——科学与技术〕
1. Many of them use chemicals to kill weeds(杂草). The trouble is that these weedkillers also kill wildlife, pollute rivers and are bad for the fields. 2. This kind of robot can cut weedkiller use by 90%. The robot is really smart. It only kills weeds but not crops(庄稼).
3.
Several cameras are built into the robot. The cameras facing the ground take photos to help the robot "see" the plants it passes.
The robot compares each photo with a library of plant photos to decide on which plants are weeds.
Robot arms move into position to spray a small dose of weedkiller on the weeds.
The robot is energy-friendly. 4.
How will the robot develop?
The scientists do not want to just stop at the achievement they have made. 5. The improved model of the robot will exactly discover weeds and dig them out instead of using weedkillers.
Robots could be programmed to leave some harmless weeds in the fields to support wildlife living there.
A. But scientists have created a farm robot.
B. It is powered by solar energy.
C. Where is the robot used?
D. They're working on the new designs to improve the model.
E. How does the robot work?
F. How do farmers usually kill weeds in the fields?

四、1~5. FAEBD