交作业：

发现了那架波音 737 Max 9 在飞行中掉落的门塞的波特兰科学老师Bob Sauer认为他后院的树木可能帮助保存了证据，“树木像安全气囊一样阻止坠落，所以它没有猛烈撞击地面。”

Portland science teacher Bob Sauer, who found the Boeing 737 Max 9  door plug falling during the flight, believes the trees in his backyard probably helped preserve evidence. "the trees  like the airbag prevented door plug from falling hard , so it did not slam into the ground", he said.