The research lacks  evidence, and therefore, its conclusions are doubtful.

----Thank god, you finally returned home _____.----You can never imagine how I worried about you when I was told about the terrible accident.

The government must be very _____ about setting policies and make no decision until they are quite sure it is the right one.

After a whole day’s heavy work ,the old worker returned home ,______________________.

During his five-day state visit to Japan, Hu Jintao  made  such an ________ speech that all the people present were ________.