填空题

We all scream for water when thirsty, but do you know in very hot, dry weather, plants also make (36) sounds as if they are crying out for help You see, in a plant stem there are hundreds of water pipes that bring water and (37) from the soil all the way up to the leaves. As the ground (38) dry, it becomes harder and harder for the plants to do this. In (39) draughts, plants have to fight to pull out any water (40) . Scientist Robert Winter has found out that when it is really bad their water pipes snap(绷断) from the (41) like rubber bands. When that happens, the whole plant vibrates(振动)a little. The snapping pipes make noises ten thousand times quieter than a (42) . Robert knows that healthy, (43) plants are quiet. (44) . How do the insects know which are healthy plants and which are not Robert thinks that the insects may listen for the plants that cry and then they may buzz in to kill. (45) .He attaches it to a quiet, healthy plant so that the plant sounds thirty. (46) . They could build traps that imitate crying plants so when the insects buzz in to eat, they won’t buzz out.