单项选择题
What is the purpose of analyzing the speed of sound through the Pacific-Ocean（）
A．To determine whether the Earth’s temperature is going up. B．To study the behavior of some sea animals. C．To measure the depths of the ocean. D．To measure the movement of waves on the ocean.
单项选择题 Why is the man afraid he won’t be able to attend the seminar（）
单项选择题 What does the woman mean（）
单项选择题 Why is their mother unhappy（）
