— How many books did you borrow in the library?
— Three. I borrowed one yesterday and ________ two this morning.
A:other
B:the others
C:another
当太阳直射23.5°N纬线时下列说法正确的是( )
某尿素【CO(NH2)2】化肥样品(杂质中不含氮元素)中含氮元素为43%,则此尿素化肥样品的纯度为( )
已知ba=23,则aa+b的值是( )