It is not easy to tell the True  _____  the False in the English reading.

I have tried so hard but _____ I get nothing.

This famous drawing is sold ____ 10,000,000 dollars.

I can hardly work out the answer _____ this difficult question.

I got a letter this afternoon. It was ____ my foreign friend.

I’m all ____ sea and I’ve no idea how to fix my pencil box.

We built this factory ______ top speed and minimum(最少的) cost.

There is a big and beautiful lake ______ the foot of the hill.

We go _____ duty at 8 a.m.

Li and I arrived ______ Heishan country safe and sound, all is well. Don’t be worry.