请选择DCBA1n)F5p5v,~(l7B+L1C There are________ stars in the sky, but some of them are too far to be seen.(o-t2|+b2h
A. thousands(o-t2|+b2h
B. thousands of(o-t2|+b2h
C. thousand of(o-t2|+b2h
D. several thousand(o-t2|+b2h