单项选择题
Your Math instructor would have been happy to give you a make-up examination, had you gone and explained that your parents were ill at the time.（）
A．如果你向你的数学老师解释你父母那时生病了，他会乐于给你一次补考机会的。 B．只要你向你的数学老师解释了你父母那时生病的原因，他会乐于给你一次补考机会的。 C．你的数学老师听到你父母那时生病的情况后，他会乐于给你一次补课的机会。 D．你的数学老师会高兴你把你父母那时生病的情况告诉他，他会给你一次补课的机会。
单项选择题 Any time during the day may be employed in physical exercise, but provided it is not too near meal hours（）
单项选择题 Since the beginning of the 21 st century, the government has started（）
单项选择题 For decades, milk was considered a luxury drink because common people （）.
