With nothing ________ to burn, the fire became weak and finally died out.
A:leaving
B:left
C:leave
D:to leave
把人体各主要组织与其相应功能用线连接起来.
A上皮组织____ a具有收缩、舒张等功能
B肌肉组织____ b具有保护、分泌等功能
C神经组织____ c具有支持、连接、保护、营养等功能
D结缔组织____ d能够产生和传导兴奋