Evidence has been found through years of study ______ children’s early sleeping problems are likely to continue when they grow up.[ ]

A. why

B. how

C. whether

D. that

影响人身触电危险程度的因素除了触电电流和触电时间的因素外，还和以下因素有关（）

A、人体电阻

B、接触电压

C、电流频率

D、电流流经人体的途径