_____the problem of land erosion getting more serious, the government is searching for a way to deal with it.
229. Look! The shop isn’t open yet. We _____.
228. Oh, the classroom is so dirty. It needs ______ before we begin our class.
227. It is necessary that the question _______ at once.
226. Einstein lived the rest of his life quietly in America and _____ American nationality in 1940.
225. I didn’t hear the phone last night. I _____asleep.