1.You should take more exercise because that’s the way to get fit.

→If you want to keep fit, You should take more exercise

2.The accident happened because the driver in front stopped so suddenly.

→ If the driver in front hadn't stopped so suddenly,the accident wouldn't have happened.

3.I haven’t got a key, so I can’t get in.

→ If I got a key,I could get in

4.Throw a stone into water and it sinks

.→ If you Throw a stone into water , it will sink

5.I didn’t have any breakfast, and now I’m hungry.

→ If I had breakfast,I wouldn't be hungry now.

6.Road travel is cheaper than rail travel in this country, so we have lots of traffic jams.

→ If Road travel weren't cheaper than rail travel in this country, we wouldn't have lots of traffic jams.

7.Martin failed his driving test last week. He was very nervous and that’s why he failed.

→ If Martin hadn't been very nervous and that’s why he failed,he wouldn't have failed his driving test last week.

8.You may want a chat, so just give me a ring.

→ If You want a chat, give me a ring.

9.I didn’t finish my report yesterday, so I can’t begin a new project today.

→ If I had finished my report yesterday ,I would have begun a new project today.

10.The wind is blowing hard, so I won’t take the boat out for ride.

→ If The wind weren't blowing hard, I would take the boat out for ride.