双曲线$\frac{x^2}{m^2+12}-\frac{y^2}{4-m^2}=1$的焦距是（   ）

我国第一个五年计划的重点是优先发展（  ）

①The school ____（旅行）is from November 12 to 13. The students will have fun.

②-Do you have an Art F____（节日）?

   -No, we don't.

③They have a birthday p____（聚会）for her son.

④His brother is the first in the English ____（测试）．

⑤I'm very ____（忙碌）now, so I can't go with you.

⑥There are twelve ____（月）in a year.

某红外线遥控器发出的红外线波长为0.000 000 94m，用科学记数法表示这个数为（   ）