— The box is too heavy to carry. What's in it?
— Jack _______ it with many books.
A:filled
B:covered
C:used
D:asked
是地球上最宝贵的东西,地球因它的存在而生机勃勃。 ()
解不等式2x-13﹣5x+12≥1,并把它的解集在数轴上表示出来.