如图表示长期使用一种农药后，害虫种群密度的变化情况．下列有关叙述不正确的是（　　）

    Jenny is Mr. White's little daughter. She is good at Art . But she isn't good at Math. Mr. White is teaching her ,”What's six plus three?”

    Jenny counts her fingers and answers ,”It's nine .”

    “Good .What's twenty minus three?”

    Anna counts her fingers and toes. “Mm.it's five .No , it's seventeen .”Jenny answers slowly.

    “What's eleven plus twelve, then ?”Jenny looks at her fingers and toes . They are not enough (足够). Seeing this , Mr. White isn't glad and says, “Use your head, Jenny .”

    “That's not enough .I've got only one head.”

根据短文内容，判断下列句子是否正确。