問3 [A ]を補うのに,次の0~④の文を文所脈に合うように並べかえ番号で答えなさい。
O Blood flows out into the arteries.
(2) Blood comes in through the veins and once more the heart is full of blood.
3 Then the heart stops squeezing and opens up again.
の The heart squeezes and gives the blood a push.
