——What ____________ you _____________ last weekend?——I wrote some letters and read a book.
A:do, do
B:did, do
C:will, do
D:have, done
It begins at two o'clock the afternoon.
读经纬网图,下列关于甲乙丙丁四点的说法,正确的是( )
互为同素异形体的一组物质是()