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

语法填空（课文改编） B1U5 Into the wild Passage 1 The Monarch’s Journey Many animals move from one place to another at certain times of the year. This annual movement is called migration. They migrate to find food, seek a partner, or ______ search of warmer weather. One of the most wonderful migrations in nature is that of the North American monarch butterfly. Every autumn, ___________(million) of these beautiful insects with fine black and orange wings begin a long and difficult journey. Somehow they manage to travel around 4,000 kilometers south and find their way to California or Mexico. However, until recently no one knew how 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 to measure the position of the sun. These two pieces of information -- the time of day and the point where the sun is in the sky -- allow the butterfly to determine the way to go. _________(eventual), it manages to reach the place where it will spend the winter. The solution______ the mystery of the monarch’s amazing ability comes at a time when it is in serious trouble. Its population _____________(crash) by as mush as 90 per cent in the last few years. Sadly, human activity is the main reason __________ the number of monarch butterflies is falling. In many of the places where the butterfly can _________(find), people are destroying the natural environment. They cut down trees and use chemicals that kill the plants that monarch caterpillars eat. The research on the monarch’s behaviour has however led to a greater awareness of this creature. People have been working together to record its migration and make sure that there are enough plants for it to feed __________. If this works, there may come a time when_________ number of monarch butterflies increases once again. The more we know about this lovely creature, the greater th