Поставьте предложения в отрицательной форме: 1. professor continued his studies on muscles. 2. the bones of the skull adjoin to those of the shoulder girdle. 3 the hind extremities usually are greater than fore ones. 4. all the ribs are attached to the breastbone.5. bones of the skull have many cartilages.

1. Professor did not continue his studies on muscles.
2. The bones of the skull do not adjoin to those of the shoulder girdle.
3 The hind extremities usually are not greater than fore ones.
4. All the ribs are not attached to the breastbone.
5. Bones of the skull do not have many cartilages.