3.1用系统命名法命名下列化合物-|||-a. (C(H)_(3)C(H)_(2))_(2)C=C(H)_(2)-|||-b. CH3CH2 CH2CCH 2(CH2)2 CH3-|||-C. (H)_(3)C=CHCHC(H)_(2)C(H)_(3)-|||-C2H5 CH3-|||-d. (C(H)_(3))_(2)CHC(H)_(2)CH=C(C(H)_(3))_(2)