A、Last week. B、Three weeks ago. C、Two months ago. D、Three years ago. B细节题。文章详细说明了购物中心的情况：花费三年打造，终于在三个星期前正式营业，比预期晚了两个月，故选B。由选项可知，

To finish today’s program, I want to tell you about the Waterside Shopping Centre, near Northport, which I visited last week. It has something for everyone and I would recommend it for a day out. It’s taken three years to build and finally opened three weeks ago, two months later than planned.
    Firstly, getting there; there are organized coach trips from most towns in the area but they leave early and come home very late, so I drove. There are 12,000 free parking spaces, so parking is no problem. You can also get there by train, but the station is 15 minutes from Waterside by bus, and the buses are really crowded, so you sometimes have a long wait.
    The shopping centre is arranged on three levels. You’ll find all your favorites here. In fact if you want to buy a pair of shoes there are 15 different shops to choose from on levels one and two. When you run out of money there are seven different banks, but collect your money before you get to the third level as there aren’t any banks up there. On that level, however, there are several restaurants, as well as a cinema with seven screens. And don’t get lost like I did, go to the information desk on the first level and get a map.
    Before you go back to your car or the bus—and in fact it might be better to do this before you go shopping and have too much to carry—go and see the lake. Take a walk or have a go at fishing, sailing or windsurfing if you have time. Or you can rest your tired feet and watch the birds and ducks, but you are asked not to feed them.
19. When was the shopping center opened?
20. What is the best way of traveling to Waterside according to the speaker?
21. What can you do on the third level?
22. Apart from shopping, what else can you do at Waterside?