按要求转换下列句式。

1. Lucy usually cleans the cage every two days.  (对画线部分提问)

    _____ _____ _____ Lucy usually clean the cage?

2. Jack's grandfather doesn't know how he should use a computer. (改为简单句)

    Jack's grandfather doesn't know how _____ _____ a computer.

什么叫原型法？试述其优缺点与适用场合。