Question

complete the text with the correct pair of words.
the biologist _ the slide under the microscope and _ began analyzing the cellular structure of the muscle tissue.
set...then
sit...then
sit...than
set...than

Explanation:

• "Set" means to place something in a particular position, which makes sense for placing the slide under the microscope.
• "Then" is used to indicate a sequence of actions (first set the slide, then analyze).
• "Sit" means to be in a seated position, which is not relevant here.
• "Than" is used for comparisons (e.g., "bigger than"), not for sequence.

Answer:

set...then