A: —I'm ____ (sad; excited) because we're going to climb the mountain.
B: —That's ____(grey; great).
A: —I'm ____(scared; tired).
B: —Why are you scared?
A: —Because she's going into the cave. I heard a____ (toys; noise).
B: —Be careful!
60kg的人站在跷跷板某一位置时,跷跷板处于如图所示的平衡状态.由此可估测球的质量约为
把下列十进制数化成二进制数:
(1)139(10)=____ .
(2)312(10)=____ .
(3)477(10)=____ .
党的十八届三中全会决定,启动一方是独生子女的夫妇可生育两个孩子的政策,表明我国()