A:①②
B:①③
C:②④
D:③④
要减少黄河的泥沙,最关键是( )
某岩石呈灰白色,可见结晶颗粒,遇稀盐酸强烈起沟,具层理构造。该岩石可定命为( )
Mr. Black is going to marry a girl he ________ in Japan last year.