Health is very important to us. We should eat more vegetables and fruit ____ too much rich food.[ ]

A. instead of  

B. instead  

C. replace  

D. stand for

有效接地系统和低电阻接地系统中，发电厂、变电所电气装置保护接地的接地电阻，一般情况下应符合（）要求。

A、R≤50/I，且不宜大于30Ω

B、R≤120/I，且不应大于20Ω

C、R≤250/I，且不宜大于10Ω

D、R≤2000/I，且不得大于5Ω