Unit 5 Into the wild. 课文语法填空（知识点总复习） -2023-2024学年高中英语外研版（2019）必修第一册

新外研必修一 Unit 5 Into the wild Understanding ideas The Monarch’s Journey Many animals move from one place to another at certain times of the year. This annual _______ (move) is called migration. They migrate to find food, seek a partner, or in search _______ warmer weather. One of the most wonderful _______ (migrate) in nature is that of the North American monarch butterfly. Every autumn, millions of these beautiful insects with fine black and orange wings begin a long and difficult journey. Somehow they manage _______ (travel) around 4,000 kilometres south and find their way to California or Mexico. _______, until recently no one knew _______ they did this. A team of scientists _______ (lead) by Professor Eli Shlizerman at the University of Washington has now found the answer. They have found out that the monarch is able to tell the time of day. It uses its eyes _______ (measure) the position of the sun. These two pieces of _______ (inform) — the time of day and the point _______ the sun is in the sky — allow the butterfly to determine the way to go. _______ (eventual), it manages to reach the places _______ it will spend the winter. The solution _______ the mystery of the monarch’s amazing ability comes at a time _______ it is in serious trouble. Its population _______ (crash) by as much as 90 per cent in the last few years. Sadly, human activity is the main reason _______ the number of monarch butterflies _______ (be) falling. In many of the places _______ the butterfly can be found, people are destroying the ________ (nature) environment. They cut down trees and use chemicals _______ kill the plants that monarch caterpillars eat. The research on the monarch’s behaviour has however led to a greater _______ (aware) of this creature. People have been working together to record its migration and make sure that there are enough plants for it _______ (feed) on. If this works, there may come a time _______ the number of monarch butterflies _______ (increase) once again.