在下面的横线上填入正确的单词。

①Thirteen plus ____ equals twenty-five.

② ____ plus eight equals forty-eight.

③Forty-five plus fifty-five equals ____.

④Twenty-four plus ____ equals eighty-two.

⑤Eight plus two equals ____.

使小狗建立“铃声﹣﹣唾液分泌”条件反射的适当方法是（    ）

（____）⑴Open your mouth.

（____）⑵Touch your nose.

（____）⑶Stamp your foot.

（____）⑷Wave your arms.

（____）⑸Shake your legs.

A.     B.     C.     D.     E.