A：加CaCl2溶液
B：加热
C：加稀盐酸
D：加澄清的石灰水
麝牛成群生活时，如果遇到狼群，雄牛会围成一团圈，头朝外面，把雌牛和小牛围在圈内，避免被狼伤害，这种现象称为（ ）
用方框中所给单词的适当形式填空，使短文通顺、正确、连贯（每个单词限用一次）。
hair, never, old, newspaper, play, but, can't, get, glasses, build
My grandfather is seventy years old, ____ he is still very healthy. He is tall and of medium ____ . He has short straight white ____ He likes reading. Every morning he ____ up very early and then reads morning ____ . When he reads, he always wears ____ . He also likes ____ chess, too. He always plays chess with his ____ friends. He ____ plays chess with me. Why? Because I ____ play chess.
产假安排（单位：周）
14
15
16
17
18
有生育意愿家庭数
4
8
20
26
