The engineers in this lab spent several weeks _______their plans for the new bicycle.

We are _______ at the rapid progress Mark has made in this semester.

ProfessorSmithisalsothe_______oftheinternationalprogramoffice.Ifyouhaveanyproblemwhenyoustudyhere,youmaygotohimforhelp.

If you have any problems during your study here,please do not _______ to call me for help

With the _______of Mary, all the girl students are eager to go to the party.