... of the present simple, the `-ing' form or present participle, and the `-ed' form used for the past simple and for the past participle. ask* asks* asking* asked dance* dances* ... For more material and information, please visit Tai Lieu Du Hoc at www.tailieuduhoc.org 3 When you use an imperative, you can be more polite by adding one of the following question tags. ... before the subject. Do they do the work themselves? Did you do an `O' Level in German? 3 If the main verb is `have', you usually put `do', `does', or `did' before...