MOST BIRDS USUALLY ______ IF THEY CANNOT SING WELL. A. WARN OTHER BI...

Câu 15: Most birds usually ______ if they cannot sing well. A. warn other birds to go away B. fly in the sky C. give information in another way D. find a wife Đọc kỹ đoạn văn sau và chọn phương án đúng (ứng với A hoặc B, C, D) cho mỗi chỗ trống từ 16 đến 20. Driving a car can be expensive. The bicycle, on the other hand, is a cheap form of (16)______ because it doesn’t need any fuel. In fact, it costs practically nothing after you’ve bought it. It also helps keep you fit because you get exercise when you ride it. Another good thing (17)______ a bicycle is that it doesn’t pollute the air. If everyone rode bicycles instead of driving cars, we wouldn’t be using up the world’s oil so quickly. While the bicycle has these advantages, it has some disadvantages too. It is convenient only for relatively short journeys, (18)______ you can travel quite a long way in comfort in a car. Another problem is that the cyclist is not protected from the weather and gets wet when it rains. Cycling isn’t very nice in heavy traffic (19)______. The best place for a bike ride is a quiet country lane. Main roads and city streets are often so busy that it needs some courage to (20)______ a bike on them.