Which sentence is written in the past perfect progressive tense?

You need to start an experiment and the instructions are to mix 2 g of sodium bicarbonate with 50 ml of distilled water and then mix the solution. describe what lab apparatus you would use and what safety precautions you must observe when completing this experiment.

The development of new inventions in the field of space travel seemed rapid. how does the word rapid function in a sentence?

In order to restrict editing to a document, a user will go to review, , restrict editing, and will then select what kinds of editing are allowed.