Trong dao động cưỡng bức thì

A. cả gia tốc, vận tốc và li độ đều biến thiên điểu hòa theo thời gian.

B. cả gia tốc, vận tốc và li độ đều giảm dần theo thời gian.

C. gia tốc và li độ biến thiên điều hòa còn vận tốc biến đổi đều theo thời gian.

D. gia tốc không đổi còn vận tốc và li độ biến thiên điểu hòa theo thời gian.

v Read the following passage and mark the letter A, B, C or D to indicate the best option for each of the blanks.

The Industrial Revolution in Britain was built on the use of machines in factories. Since the 1950s, Britain's (34) _______ industries have replaced machine operators with computers, and this (35) ________ has led to a decline in the number of (36) ________ in many factories. Goods are bought and used much more than ever before but a lot of these goods are imported. By the beginning of the 20th century, other industrial countries like the USA were (37) ________ with Britain's exports, and countries in the Far East have been able to provide cheaper (38) _________since the 1970s. Areas located with heavy industries are suffering high unemployment. During the last 30 years, there has been a constant rise in smaller industries (39) ________ as "light industries". These ones use electricity and are not (40) _________ on raw materials such as coal so they are "footloose", i.e. they can be located anywhere. They produce such things as washing machines or spare (41) ________. Some of these industries produce nothing at all, but provide services like distribution. The consumer boom of the 1980s and the increased leisure time of most Britons have led to rapid (42) ________ in service industries like banking, tourism, retailing and information processing, and in industries which distribute, maintain, and repair (43) _________ consumer goods.

Điền vào câu 41

A. details

B. parts

C. sections

D. gadgets