:27,16,5,(),17。
A.16 B.1 C.0 D.2
27,16,5,(),1/7 A.16;B.1;C.0;D.2;
2/3,1/4,2/5,(),2/7,1/16, A.1/5;B.1/17;C.1/22; D
1/16,1/27,1/16,1/5,______,7 () A.1/16 B.1 C.2 D.1/24
2, 3, 5, 7, 12, 15, (), () A.26,31 B.17,21 C.27,31 D.16,21
27,16,5,(),1/7。 A.16 B.1 C.0 D.2
27,16,5,(),1/7。A.16 B.1 C.0 D.2