一、单项选择（10分）
1.Many companies suffer ______ a shortage of skilled workers .
A , at B to C for D from
2.The kids offered _______ the dishes .
A do B to do C doing D does
3.Mr Li asks the students______ in the river ,because it’s too dangerous .
A swim B to swim C not to sw im D to not swim
4.Do you know that the Earth is home to _____animals.
A million B millions C millions of D million of
