What are you doing?—I’m thinking _____ life in the countryside. [ ]

Which of these two sweaters will you take?–I’ll take . They look nearly the same, and I just need one.

Some Maths problems in this book are difficult for the students work out.[ ]

My father often brings me____, so I’m always happy when he comes back.

Where’s the key to the car, Li Tao? ––I can’t remember ____ last night.