ponder|pondered|pondering

哲学家经常仔细思考存在的基本问题。

Philosophers often ___ponder the fundamental questions of existence.

她长时间仔细思考了自己决定的后果。

She ___pondered the consequences of her decision for a long time.

我仍在仔细思考生命的意义，对答案不确定。

I am still ___pondering the meaning of life, unsure of the answers.