私は一人で地下鉄で学校に通っていますって英語でなんて言うの？

I use the subway to go to school by myself. I go to school using the subway by myself. I ride the subway to go to school all alone. I don't take anyone with me to ride the subway to school. Nobody goes with me on the subway to school.

"I ride the subway on my own to go to school" This sentence is expressing that you 'ride'/take/use the 'subway'/train(mode of transportation) to get to school. "I take the subway alone to get to school" To 'Take the..' is used as a reference to take/use/ride a type of transportation. 'Alone' is a term used to describe being by yourself.

When explaining how you go to school, you want to explain that you ride the subway by yourself to go to school.

If you do someone on your own then you do it by yourself so would say 'by myself' you can also say 'alone' when you go on the subway you can say you 'ride' the subway or you 'take' the subway 'to go to school' or 'to get to school' explains where you are going

To explain that you use the subway to get to school, the above examples may be used. Bypass: go around or past. Convenient: Helpful, comes in handy, makes things easy. The subway is a quick and convenient mode of transport for many people like students, business workers, teachers and anyone who needs a quick ride. It operates underground and so it is able to bypass all traffic and any other obstructions. It is good for the environment (environmentally-friendly) as it transports many people at once cutting down on the CO2 that would have been discharged by cars.