Great Scientists教案
scientists know that mosquitoes find some people more attractive than others, but they do not know why. they also know that people 26 in their reactions to mosquito bites. one person has a painful swelling while another who is bitten by the same mosquito, may hardly notice. scientists have not yet discovered the reason for this, but they have 27 experiments to show that mosquitoes are attracted to, or put off by, certain smells. 28 , scientists will be able to develop a smell that mosquitoes cannot 29 in the future. this could be placed in a net to 30 mosquitoes that fly in. for the time being however, we have to continue spraying ourselves with unpleasant liquids if we want to avoid getting bitten.21. a. voice b. noise c. song d. cry22. a. astonishing b. common c. impossible d. boring23. a. diseases b. guilty c. sorrow d. panic24. a. expensive b. effortless c. effective d. limited25. a. chemicals b. illness c. reactions d. drawbacks26. a. put b. take c. vary d. balance