____ speaking, a person must care much about his ____, because it is not only a personal thing, but also a social one.

. —Li Hua was in London for two years.   —It’s no ___ he can speak English so well.

The difficulties they are facing are just beyond          though they are determined to continue their research.

Tom succeeded, for he had made a great ______ and got over plenty of difficulties.

The police always take ________ of dogs’ sharp sense of smell to search for the survivors in the earthquake.