阅读对话, 选择正确答案
A: What time is it, Mingming?
B: It's eight o'clock.
A: OK. Let's count the rulers. How many rulers are there'?
B: One, two, three... Twelve rulers.
A: What colour are they?
B: They're yellow.
A: How many pens are there?
B: Two pens.
A: Good!