9. The price on this packet is wrong. It says $65 but it ___________ $50.
A. canbe
B. will be
C. shall be
D. shouldbe
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10. He says he's 21 but he __________ older than 18.
A. need not be
B. shall not be
C. darenot be
D. can't be
选出全是促进石墨化的元素的一组（ ）
A. Mg、B、Cu
B. V、Cr、S
C. W、Mn、P
D. Al、Ni、Si
灰铸铁常用的孕育剂是（ ）
A. Ti
B. Mn
C. 硅铁和硅钙合金
D. 钠盐
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