未知题型 We’ll visit Europe next year _________ we have enough money.A) lest B) until C) unless D) provided

未知题型 If the building project___________ by the end of this month is delayed, the construction company will be fined.

未知题型 Though he was born and brought up in America, he can speak ___________ Chinese.A)fluid B) smooth C) fluent D) flowing