When I was a child, my mother taught me not to get into a car with a stranger.
When my car broke down, a kind stranger stopped to help me.
A foreigner is someone who comes from another country:
This town is a popular tourist destination, so there are always a lot of foreigners around.
The new law makes it easier for foreigners to get documents to work legally.
A lot of foreigners have been moving into this neighborhood - I've met people from seven different countries in my apartment building alone!
The word alien is a legal term for foreigner. It is usually used to describe "illegal aliens" (people who are in the country illegally) or "resident aliens" (people who are living in the country legally). Again, this is formal/legal language and in everyday speaking it's best to use foreigner.
Alien also refers to creatures from other planets; it is another word for extraterrestrial.
To vent the fuel that remains after the engine stalls or if the engine cannot be run to
consume the fuel, the CNG can be vented safely into the atmosphere. Special precautions
are necessary to safely vent the CNG without causing a fire. NFPA 52 Vehicular
Gaseous Fuel Systems Code, the International Fire Code and some state and local regulations
require that any venting system be approved by the Authority Having Jurisdiction
AHJ, generally the fire marshal. Always use a vent system approved by the AHJ.
If the vehicle is equipped with a special connection to transfer fuel out, it can be connected
to the approved vent system and emptied as in the direct defueling example,
making sure that the solenoid valves open.