Заполните имеющиеся в предложениях пропуски модальными глаголами ought to, must, might, can, may. В некоторых возможно употребление нескольких модальных глаголов.

1. They...... go home now if they want.
2. It .......be weeks before the building will be actually finished.
3. You ....... even find a new job by then, who knows?
4. That ...... be Tim coming home now. He always comes home at this hour.
5. You... not talk to your grandmother like that
6. ........ you remember the name of that restaurant?
7. My hair is too long. I ........ get my hair cut.
8. It is cloudy. I think it ...... rain later.
9. Workers ....... not to leave the office before 5 p.m

In 1795, a man named comte invented a pencil made of a mixture of graphite and some sorts of clays which were burnt in the furnace. "simple" pencils are made of graphite, which leaves a dark trail on paper. in the process of pencil manufacturing, dry graphite powder is mixed with clay and water. the more clay there is, the harder the pencil and the more graphite, the softer is the pencil. wood billets of cedar or pine are cut in half alongside and a groove is cut out for the lead. both halves of the pencil are then glued together. the billets are cut into pencils whose surface is polished. today more than 300 different kinds of pencils are produced for various purposes. there are pencils for writing and leaving trace on such surfaces as glass, fabric, cellophane, celluloid and plastic, which are used in construction .