Ⅰ.单句语法填空/单句改错
1．It seems good________theory，but it doesn’t work in practice.
答案： in
2．The policeman ________(signal)to the truck to stop.
答案： signalled
3．Although they had tried all the means，the proposal failed to go________.
答案： through
4．Even the best writers sometimes find themselves________ (lose) for words.
答案： lost
5．People between 18 and 40 make________the largest percentage of people who speak a foreign language.
答案： up
