Barack Obama is the 44th president of the United States. He is the first African-American to hold the office, while his predecessors are all  ______ Americans.
(A) native
(B)Republican
(C) Caucasian
(D)Democratic
n.[C] 1. 前任; 前輩 He is working hard to excel his predecessors. 他正努力超越他的前任。 2. (被取代的)原有事物 The new proposal is better than its predecessor. 新建議比以前的建議好。 3. 【古】祖先