All are grammatically correct. Which colours you use in various projects depends on desired emphasis and style.

In 1 the emphasis is on recognition, whereas in 2 and 3 the emphasis is on the object.

If you want to emphasize recognition I prefer 2 to 3, because the use of the passive in 3 makes the sentence more complex without adding anything.

I have over 15 years of teaching English to foreigners.

All are grammatically correct. Which colours you use in various projects depends on desired emphasis and style.

In 1 the emphasis is on recognition, whereas in 2 and 3 the emphasis is on the object.

If you want to emphasize recognition I prefer 2 to 3, because the use of the passive in 3 makes the sentence more complex without adding anything.

I have over 15 years of teaching English to foreigners.

All are grammatically correct. Which colours you use in various projects depends on desired emphasis and style.

In 1 the emphasis is on recognition, whereas in 2 and 3 the emphasis is on the object.

If you want to emphasize recognition I prefer 2 to 3, because the use of the passive in 3 makes the sentence more complex without adding anything.

I have over 15 years of teaching English to foreigners.

All are grammatically correct. Which colours you use in various projects depends on desired emphasis and style.

In 1 the emphasis is on recognition, whereas in 2 and 3 the emphasis is on the object.

If you want to emphasize recognition I prefer 2 to 3, because the use of the passive in 3 makes the sentence more complex without adding anything.

I have over 15 years of teaching English to foreigners.

All are grammatically correct. Which colours you use in various projects depends on desired emphasis and style.

In 1 the emphasis is on recognition, whereas in 2 and 3 the emphasis is on the object.

If you want to emphasize recognition I prefer 2 to 3, because the use of the passive in 3 makes the sentence more complex without adding anything.

I have over 15 years of teaching English to foreigners.

All are grammatically correct. Which colours you use in various projects depends on desired emphasis and style.

In 1 the emphasis is on recognition, whereas in 2 and 3 the emphasis is on the object.

If you want to emphasize recognition I prefer 2 to 3, because the use of the passive in 3 makes the sentence more complex without adding anything.

I have over 15 years of teaching English to foreigners.

All are grammatically correct. Which colours you use in various projects depends on desired emphasis and style.

In 1 the emphasis is on recognition, whereas in 2 and 3 the emphasis is on the object.

If you want to emphasize recognition I prefer 2 to 3, because the use of the passive in 3 makes the sentence more complex without adding anything.

I have over 15 years of teaching English to foreigners.

All are grammatically correct. Which colours you use in various projects depends on desired emphasis and style.

In 1 the emphasis is on recognition, whereas in 2 and 3 the emphasis is on the object.

If you want to emphasize recognition I prefer 2 to 3, because the use of the passive in 3 makes the sentence more complex without adding anything.

I have over 15 years of teaching English to foreigners.

All are grammatically correct. Which colours you use in various projects depends on desired emphasis and style.

In 1 the emphasis is on recognition, whereas in 2 and 3 the emphasis is on the object.

If you want to emphasize recognition I prefer 2 to 3, because the use of the passive in 3 makes the sentence more complex without adding anything.

I have over 15 years of teaching English to foreigners.

All are grammatically correct. Which colours you use in various projects depends on desired emphasis and style.

In 1 the emphasis is on recognition, whereas in 2 and 3 the emphasis is on the object.

If you want to emphasize recognition I prefer 2 to 3, because the use of the passive in 3 makes the sentence more complex without adding anything.

I have over 15 years of teaching English to foreigners.