婴幼儿睡眠时应任其按（）熟睡。
A.生长发育规律
B.睡眠规律
C.生理规律
D.大脑中枢需要
参考答案：B
填入适当的基数词，完成句子。
1. What's ___________ and five? It's twenty.
2. What's seventy and ___________? It's one hundred.
3. What's ___________ and eighteen? It's fifty-nine.
4. What's ___________ and thirteen? It's sixty-two.
5. What's ___________ and eight? It's ninety-seven.
如果a+1=b（且a、b都不为0的自然数），它们的最大公因数是______，最小公倍数是______．
