n 2 为单质,则2113n元素的化合价为52610;no中o为-2价,由化合物中正负化合价的代数4102和为16530,则n元素的化合价为+2价;no 2 中o为-2价,由化合物中正负化合价的代数和为0,则n元素的化合价为+4价;nh 4 no 3 中氨根为+1价,**根为-价,则氨根中n元素的化合价为-3价,**根中n元素的...
be in over your head:to be involved in a difficult situation that you cannot get out of eg.sean tried to pay h** gambling debts,but he was in over h** head. ...
industry ** already using one form of the invention to deal with he**y loads. it can lift them with ease and since there are no wheels, and therefore no friction, they can be put into motion with the ...
这的区别需要在语境中区别:1. was 1) there was books in the box. 箱子里没有处意为:没有) 2)it was good saying that. 那样说没有好处。(意为:没有)2.was not 1)he wasn't very happy yesterday. 昨天他不太高兴。(此处意为:不是) 2) was not ...