阅读理解

       It’s a sunny and warm spring Sunday morning. There is no cloud in the sky. The sun is shining

brightly and the birds are singing happily. The Smith family are at home in the yard (院子). They are

doing their own things. Mr. Smith is planting flowers and trees. Mrs. Smith is drinking lemonade and

reading a book. Mary Smith is playing with the dog. Billy Smith is listening to the radio and dancing.

And Sam Smith is playing the guitar and singing some beautiful songs.The Smiths are very happy today.

It’s a beautiful day and they’re busy at home in the yard. What a nice day! What a happy family!

1. What is the weather like today?

                                                          .

2. What are Mr. Smith and Mrs Smith doing?

                                                          .

3. What is Billy doing?

                                                            .

4. What is Sam doing?

                                                            .

5. Is Mary playing with the dog?

                                                              .

电子控制自动变速器的执行装置，主要是（）。