单项选择题
In the writer's opinion, humans are the sharks' worst enemies because()
A．more than one million sharks are killed by humans every year B．there are fewer than one hundred shark attacks on humans in the world each year C．many people are afraid of sharks D．most sharks eat fish and seals and other sharks
单项选择题 There are different ______ in the pond.
单项选择题 Sharks can stop themselves from sinking because()
单项选择题 The housewives learned about the offer of free goods ()
