【单选题】MV SKYCLIPPER RE OUR TELCONV YDAY N PREVEIOUS TLX DD 24 JUL HV SPKN TO OWNER N UR RECFM TO Z FLWG NORDER ENSURE VSLS FXTRE TO U. Following this passage will be ______.
【单选题】A positive displacement pump is that where the volume of the pump chamber is alternately _____ to draw the liquid in and then _____ to force the liquid out.