问题

Did youunderstand what the teacher said —Yes! She explained the text in detail to make herlessons __________.
A:developed
B:This protects the plants and other forms of life that exist in the oceans
C:Sharks are valuable to us and we can make full use of them
D:easyunderstand
B:This protects the plants and other forms of life that exist in the oceans
C:Sharks are valuable to us and we can make full use of them
D:easyunderstand
正确答案是: