⑴____ A. red B. then C. ticket D. spend
⑵____ A. maths B. thank C. think D. there
⑶____ A. weather B. bread C. tea D. breakfast
⑷____ A. toy B. boy C. goat D.coin
⑸____ A. find B. film C. five D. climb
16____6=10 16____4=4
若两条抛物线的顶点相同,则称它们为“友好抛物线”,抛物线C1:y1=﹣2x2+4x+2与C2:y2=﹣x2+mx+n为“友好抛物线”.
下列关于实验仪器使用的说法中,正确的是( )