1.   Hydrogen advocates concede that the fuel ignites at a relatively low temperature and spreads quickly.

2.   If they can get the fuel to ignite, it would burn for several days.

3.   If you accelerate and hear pinging or knocking, then the fuel is probably igniting prematurely.

4.   Its fuel ignited and incinerated everything in its way.

5.   That is because when the fuel ignites, there is more air in the cylinder to expand and to push the piston down.

6.   The fuel ignited from the wick.

7.   The plane lifted off, but as the jet fuel ignited, the left-side engines malfunctioned.

8.   Unfortunately there was added stress, in the form of extremely hot fires that resulted when jet fuel ignited the contents of the buildings and planes.

9.   He refired the burner, but spilled fuel ignited and burned holes in the lower edges of the balloon.

10.   The fuel then apparently ignited, burning the workers.