下图三条曲线中分别表示当环境温度从25℃降到3℃时,小白鼠体内甲状腺激素含量、尿量及酶活性的变化情况为
A.①②③
B.①③③
C.③①②
D.①①②
答案:D
—Where is Tom?
— Well, he ______ you ______ here.Otherwise he would come down right now.
A.didn’t know; were
B.hasn’t known; are
C.doesn’t know; are
D.hadn’t known; were
乡村聚落类型及其人们从事的生产活动搭配正确的一组是[ ]
A.农村—放牧
B.牧村—伐木
C.渔村—捕鱼
D.林场—种植