The theory by Einstein was later to prove true but at that time few people could accept

问题补充：

The theory by Einstein was later to prove true, but at that time few people could accept it .

A. put out

B. put together

C. put aside

D. put forward

答案：

A. put out

B. put together

C. put aside

(答案→)D. put forward

解析：词组辨析题。A. put out 熄灭 B. put together组装 C. put aside 搁置一边 D. put forward 提出句意：爱因斯坦提出的理论后来证明是对的但是在那时很少人能理解并接受它。根据语境选D