87. Because of the noise outside, Nancy had great difficulty in focusing on her experiment。

　　或者in concentrating on her experiment。

　　88. The manager never laughed; neither has she lost her temper。

　　89. We look forward to being invited to attend the opening ceremony。

　　90. It is suggested that air conditioner (should) be installed next to the window。

　　91. The 16-year-old girl decided to travel abroad on her own despite her parents’ strong opposition。