株叶片发生烟草低头黑病时，病斑多发生在中脉或近侧脉处，叶片呈扭曲状，并通过中脉扩展到叶茎，然后蔓延到茎部，引起顶芽弯曲，整株叶片凋萎。
参考答案：对
Lots of waste has been dumped into the river, which has led to________. [ ]
A. lots of fish having been killed
B. kill lots of fish
C. lots of fish being killed
D. lots of fish to kill
根据未成年人保护法的规定，父母或者其他监护人应当依法履行对未成年人的监护职责和抚养义务。
