While Xiao Ming his homework, his mother came with a cup of tea.( )
has doing
had done
is doing
was doing
Jack may fall behind the other students in his class when he _________ back from England next week.
Lily ________ other colours ________ blue, green and yellow.
He will send me a message as soon as he _________ in London.
Nobody ______her because she has a new look.
I don’t know if Mr. Smith ____. If he ___, I will tell you.