()钢和铸铁都是以,两种元素为主构成的合金。
A.铁和锰
B.1铁和碳
C.铁和硫
D.铁和磷
参考答案:B
More foreign leaders have sent telegrams and letters recently to _____ China on the complete success of the
Beijing Olympics between Aug. 8 and 24. [ ]
A. congratulate
B. celebrate
C. express
D. expect
虱传回归热临床表现中以_____及_____为最突出的症状。