VII. Make questions to the following sentences

1. Natural gas is extremely rich in methane and contains heavy hydrocarbons.

2. The rich absorption oil and the purified condensate are fractionated by distillation to propane, butane, stabilized gasoline, and residues.

3. Large gas pipeline enable gas to be transported over thousand of kilometers.

4. Because of pressure losses, the pressure has to be boosted at regular intervals to

keep a constant flow rate in the pipeline.