完成句子：根据句意及汉语提示，用词组的适当形式填空。（每小题2分）
. Mrs. White is a kind woman. She spends most of her free time                    （照顾）these homeless dogs.
. There is                     (毫无疑问)that the engineer has made a mistake once again.
The boy’s parents are dead, so he has to                          （依靠）himself.
. Zheng He was the Ming Dynasty explorer whom all the Chinese people
（对……感到骄傲）.
. Now more and more persons walk or ride a bicycle to work                    （代替）driving a car.