Expression "Look forward to"

[Learner]

Is this the proper answer for this test? (Elementary - Test 1)

Answer 7 out of 10
I look forward seeing you on Tuesday after work.

You have found the error but your entry is incorrect
I look forward to seeing you on Tuesday after work.

I learned that "look forward to" is an expression, and the verb has to be in -ing form, but we are not supposed to omit the "to"...

Thanks for your attention

[Torsten]

Dear Learner, Many thanks for letting us know about the mistake - you are right, the correct answer is 'I looking forward to seeing you'.
We have added the 'to'.
Please contact us should you come across other mistakes.
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Test Of English for International Communication
TOEIC Preparation & TOEIC Vocabulary

[Learner]

Thank you very much for your quick answer!