A:神经纤维
B:反射弧
C:电信号
D:突触
我能把字写漂亮。
jì yì qǐ zhī yuè ěr diāo nàn
____ ____ ____ ____
最早在两河流域定居的居民是 ( )
We need a large quantity of food and water to save these homeless people.