1 . Years before the term “artificial intelligence” ____________ (coin) in the mid-1950s, the theory ____________ (explore) by Alan Turing, one of the pioneers in the field of computer science. (所给词的适当形式填空)

2 . Years before the term “artificial intelligence” ___________(coin) in the mid-1950s, the theory had been explored by Alan Turing. (所给词的适当形式填空)

3 . In another, employees were shown to be 15% more productive when their workplaces were ________(decorate) with houseplants.（所给词的适当形式填空）

4 . The cost of building a railway________(estimate) at over one hundred thousand pounds last year. (所给词的适当形式填空)

5 . Tom was told that his teammate won the race while he ________ (treat) by the team doctor. （所给词的适当形式填空）

6 . We were s ______ up into several groups to hold discussions.