Birds are singing________the sky.
A．in B．on C．at
The weather is________.
A．snow B．snowy C．snows
—Is Lisa reading books?
—Yes，________.
A．she isB．she'sC．She is
________he often clean the room on Sundays?
A．Do B．Does C．Did
Spring is coming.It's time________.
A．to plant seeds B．plant seeds C．planting seeds