问题
选择题
Unfortunately, the element Madam Curie devoted all her life her death.
A．to caused
B．causing
C．to be caused
D．to causing
答案
答案：A
本题考查动词。句中Madam Curie devoted all her life to作定语，修饰the element，主句缺少谓语动词，根据语境用一般过去时，选A。
C(s)＋2H2(g)；②2CH4(g)
C2H2(g)＋