Malls are 1) ……………………………. (popular) places to shop in America.  There are 46,990 malls in the United States of America.  The Mall of America is one of 2) ……………………………. (large) malls in the US. It is long enough to fit seven Yankee stadium’s inside! However, it is not as 3) ……………………………. (big) as Dubai Mall, which is 1.1 million square metres in size!  California has 4) ……………………………. (many) shopping malls than any other state, with 6,243 altogether.  Malls are usually open for 5) ……………………………. (long) hours than smaller shopping areas.  The 6) ……………………………. (busy) shopping day of the year is the Saturday before Christmas, as last minute shoppers hit the stores.

1. The solar lamps are lighting the tunnel. The solar lamps were lighting the tunnel. The solar lamps will be lighting the tunnel.
2. The scientist is developing a new source of energy. The scientist was developing a new source of energy. The scientist will be developing a new source of energy.
3. The engineers are working at the problem of using solar power. The engineers were working at the problem of using solar power. The engineers will be working at the problem of using solar power.
4. The people are not using poor methods of research. The people were not using poor methods of research. The people will not be using poor methods of research.
5. The students are not having an interesting discussion. The students were not having an interesting discussion. The students will not be having an interesting discussion.
6. The sun is not shining brightly. The sun was not shining brightly. The sun will not be shining brightly.
7. The workers are complaining about unsafe working conditions. The workers were complaining about unsafe working conditions. The workers will be complaining about unsafe working conditions.
8. The government is trying to protect consumers. The government was trying to protect consumers. The government will be trying to protect consumers.

1 Does she visit her friends on Saturdays? 2 When does she visit her friends? 3 She sometimes visits her friends on Saturdays, doesn't she? 4 Does she visit her friends or her family on Saturdays? 5 Who visits friends on Saturdays?

1 Did you arrive at the station at 10 o'clock? 2 When did you arrive at the station? 3 You arrived at the station at 10 o'clock yesterday, didn't you? 4 Did you arrive at the station yesterday or the day before yesterday? 5 Who arrived at the station at 10 o'clock yesterday?