(2012·浙江) According to scientists, mental abilities begin to __________ from the age of 27 after reaching the highest level at 22.
The album _______ twelve songs in all, five classic songs _______.
With more and more birds _______, some day some species will _______ completely. In addition, some of them have _______ environmental pollution.
His test results are not very consistent. He does well __________week and badly the next.
—Yousee, I'm poor in maths; you are not good atEnglish, and. . . — That's __________ we should help each other.
—Can you accompany your little brother to the post office now?—__________,if he is ready.