_____ many times, he finally understood it.
231. In 1919, the May Fourth Movement ________, beginning with a large-scale new cultural movements in China.
230. I didn’t ______ being called “Lazy bones”, because a lot of housework is always done by my elder sister.
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.