3. 解析:选A。句意为：吸烟有害健康。所以在公共场合决不允许吸烟。at no time 决不；in no time 立刻；at all times 总是；all the time 一直。at no time 位于句首时，句子用部分倒装。

2. 解析:选C。考查词义辨析。reasonable合理的；comfortable 舒适的；convenient 便利的；available 可用的。

1. 解析:选C。考查由connect构成的短语及非谓语动词的用法。connect to意为“与……连接(在一起)”；connect on无此搭配。根据句意和结构，可知此处应为过去分词作后置定语，故选C项。

5. Even though they loved each other, they decided to part.

?提升练习

4. The new skyscraper is under construction.

3. If it is convenient to you, come here tomorrow.

2. The wheels of the car were /got stuck in the mud and we could not go on.

1. Seeing from the top of the high building, you?ll have/get a good view of the whole city.

5. narrowly

3. unlimited4. imagination