在一定条件下,RO3n-和I-可发生如下反应:RO3n-+6I-+6H+=R-+3I2+3H2O,则RO3n-中R元素的化合价为( )
A.+1
B.+3
C.+5
D.+7
答案:C
—What about today's temperature?
—It's the same as, if the weather report is exact as usual, ________of yesterday.
A.one
B.that
C.ones
D.those
如果属于新建的有重大危害性的设施,应在其投入运转( )提交安全报告。
A.之前
B.之后
C.的同时
D.之后,且产生危害之前