optional extra造句怎么写

The cassette player is an optional extra in this make of car.

The cassette player is an optional extra in this make of car, ie It will cost extra if one chooses to have it.

The integrated child seat in the Passat has been awarded a prize by the German motorist association ADAC and is available as an optional extra for 255 euros (two seats for 445 euros).

Added optional extra argument to gmp_init(). The extra argument indicates which number base gmp should use when converting a string to the gmpnumber.

The car radio is an optional extra.

So, in terms of practicing this weekend, I mentioned that instead of getting a problem-set today, what I am going to be Posting is optional extra problems.