(Many) unexpected problems (have been arisen) in the course (of) the reconstruction (of) the city.

单项选择题(Even though) Sandra (has been studying) English for three years (before) she came to the United States, it is difficult for her (to express herself).

单项选择题(When) he found he (hadn't) enough money (to pay for) the meal, he was very much (embarrassing).