Bài 2: Choose the corect answer in the parentheses a) Economics ( is, are) Don`s favourite subjects b) ( Do, Does) any of you know the answer to that question c) There ( is, are) over 600,000 kinds of insects in the world? d) How many kinds of birds ( is, are) there in the world? e) Why ( is not, are not) there a hospital close to those villages?