问题
选择题
—Car prices have been going down sharply in the last 20 years.
—It's not surprising because the law of market ________ the price of a product.
A．is controlling
B．controls
C．has controlled
D．controlled
答案
答案：B
B 考察动词时态。由语境可知，市场规律控制商品价格，这是一个客观真理，因此应该使用一般现在时。故B正确。