Заполните пропуски в инструкции следующими словами
The Work of a Laboratory Assistant
1. You must 1_______ inoculating needles before and after use.
2. You must heat 2_______ in the flame until red hot.
3. You must always 3_______ test-tubes with cultures in test-tube racks.
4. You must wash your hands before leaving the 4_______.
sterilize
needles
keep
laboratory