найти площадь ромба, если его диагонали равны 4 и 12

1. He ... a good footballer. (be)  2. We ...  at school. (be)  3. The roses ... very beautiful. (be)  4. I ... an interesting book. (have)  5. The sun ... very hot. (be)  6. I ... my lessons very carefully. (do)  7. Elizabeth ... a new dress. (have)  8. The students ... English lessons three times a week. (do)  9. I ... a camera. (have)  10. Harry ... a tennis player. (be)  11.  Tony ...a coat. (have)  12. The children’s hands ... dirty. (be)  13. Mike ... late for school. (be)  14. Ted ... a good swimmer. (be)  15. Ted ... swimming very much. (like)  16. I always ... my homework. (do)  17. I ...go to school by foot. (go)