So necessary _____ it to learn about their customs that I will attend a special lecture next week.
The doctor suggested he ________with a serious disease and that he ________to hospital at once.
________I met him,he was working as a secretary in a big company.
Only when he told me ________what trouble he was in.
---It’s a long time since I saw my sister.--- ______her this weekend?
Mr. Smith,________of the ________speech,started to read a novel.