Выбрать соответствующие вспомогательные глаголы:
1) … chemistry help the doctors to prolong human life?
a) do; b) does; c) is.
2) Plastics are used especially widely in orthopaedy, … …?
a) isn’t it; b) don’t they; c) aren’t they.
3) 3. … many medical items made from polymers in our country?
a) is; b) were, c) are.
4) 4. What … widely used in dentistry?
a) do; b) are; c) is.