You "clear" the mask by blowing into it before "sealing" the mask by covering the inlet valve and breathing in. If there is chemical agent in the area when you don the mask, breathing in before clearing it will give you a lungful of deadly agent.
force the air out of the bag
The past perfect tense.
So that it can form a protective environment for the egg to develop into a baby.
The past perfect tense of "finish" is "had finished." It is used to indicate that an action was completed before another action or point in time in the past. For example, "She had finished her homework before dinner." This structure emphasizes the completion of the action prior to another event.
Past Perfect: had known, had been, had danced, had taken.
perform negative pressure check
perform negative pressure check
perform negative pressure check
Before performing negative pressure check
Before performing negative pressure check
Before performing negative pressure check
perform negative pressure check
Perform negative pressure check.
Perform negative pressure check.
Perform negative pressure check.
Perform negative pressure check.
perform negative pressure check