【正确答案】 D

【答案解析】continually“一直地(强调动作中间有停顿变化的)”，如“The baby is continually screaming.”那婴孩老是尖声喊叫。(强调中间有不哭喊的时候)；continuously“连续不断地(中间动作没有停顿)”；gradually“逐步地，渐渐地，连续不断地(中间动作没有变化)”，如In the stinging rain and the chilling snow she toils unceasingly, uncomplainingly, living wholly in the hope of her husband's return.