题目内容
Every year，millions of Monarch Butterflies(帝王蝶) fly 4,000 km from Canada Mexico and then 4,000 again. They stay in Mexico for over six months, from October to April, it is cold in Canada during(在…期间) that time. In Mexico, they lay eggs(产卵) and then die(死亡). In , the new butterflies start to fly back to . There, they die they lay eggs. Then the butterflies fly to Mexico again. Monarch Butterflies always go to the same places in Mexico and to the trees. How do they know the ? do they go to the same trees? Only Monarch Butterflies know.
1.A. by B. in C. to D. over
2.A. there B. back C. straight D. across
3.A. if B. because C. but D. and
4.A. April B. October C. November D. winter
5.A. the UK B. the USA C. Canada D. China
6.A. before B. after C. behind D. later
7.A. strong B. weak C. new D. old
8.A. same B. different C. tall D. young
9.A. path B. road C. way D. Mexico
10.A. How long B. Why C. How often D. What
