169的算术平方根是（）

哺乳动物进食时会分泌唾液，但铃声刺激不会．巴普洛夫每次在铃声后即给狗喂食，这样多次结合后，狗听到铃声就会分泌唾液．下列叙述不正确的是  （）

已知一组数据：10，8，10，8，6，13，11，10，12，9，11，12，9，10，11，10，7，8，12，9，那么频率为0.2的范围是（　　）

用括号中所给单词的适当形式完成下列句子
____ The students took the PISA test in _________ subjects - reading, maths and science. (third)
____ Board games are more and more popular among          . (teenager)
____ I liked to walk in fields on         days and to see my footprints left behind. (snow)
____people often begin their conversations by talking about the weather. (Britain)
____ The news about education has attracted the public attention        (recent)
____ The World Chocolate Park showed a         of many kinds of chocolates. (collect)
____ To improve your writing skills, you'd better         a habit of reading. (development)
____ Don't tell lies. Nobody likes those         people. (honest)