单项选择题
What measure was taken against floods in London in the 1980s（）
A．A flood wall was built. B．Rescue teams were formed. C．An alarm system was set up. D．50 underground stations were made waterproof.
单项选择题 What are the speakers doing（）
单项选择题 What happened in London a few months ago（）
单项选择题 What was the main harmful effect of the pest killer DDT on bald eagles（）
