Вставьте нужную форму глагола to be:1) Helen … my sister. 2) … Sam at your party last Saturday?3) The final tests … enough difficult next time. 4) Your new book … not so interesting as it … last year. 5) George, … you a student of Technological University? – Yes, I … an exchange student. 6) … he … in time here?7) This street … repaired last month. 8) … they here now?9) … she alone at home?10) Your smile … so stupid and inappropriate in this situation. 11) The Shannon … the biggest Irish river. 12) I … not … late to your report. 13) … a whale the biggest animal in the world?14) Tolkien, Chesterton, Lewis … the most popular British writers last century. 15) … High Math your biggest problem for you at the Institute?16) Oxford … a city in the South East region of England and the county town of Oxfordshire. 17) Pentagon … the biggest administrative building in the world. 18) In general it … very difficult to assemble devices on the atomic scale, as one has to position atoms on other atoms of comparable size and stickiness. 19) Computer revolution … the reality of the next one hundred years. 20) Ford Thunderbird of 1960 … a high-speed sedan with folding top.