factors ... lead to causes
　　fail to don't
　　fall back on turn to
　　fall back on a dictionary look up some words
　　fall back on one's dictionary look up some words
　　famous well-known
　　fan like to do sth.
　　far from being the only one many people
　　far from new old
　　fascinating very interesting
　　fascinating very interesting
　　faster than exceed
　　feeble weak
　　feeble weak
　　feedback opinion
　　feedback opinion
　　ferry boat
　　ferry boat
　　few ... sit through // out ... entire most ... leave before ... over
　　few and far between hard to find
　　field trip class activity
　　figure out // have no idea need one's help
　　fill her shoes take her place
　　fill in for replace
　　fill in for sb. replace sb. // substitute for sb.
　　fill in for sb. take the place of sb. // take over for sb. // take over (one's job)
　　fill one's shoes take one's place
　　fill out the form complete a form
　　fill out the papers complete the forms
　　fill sb. in on keep sb. informed of // bring sb. updated/up-to-date on
　　financial aid money
　　find // come up with prepare for
　　find look for
　　find out about it check on it
　　fine charge
　　fine charge
　　fine with go along with // agree
　　finish // put everything together // turn in complete
　　finish complete
　　finish complete // submit // turn in
　　finish first win
　　first start right away
　　fit as a fiddle in excellent health
　　five several
　　fix // take care of // handy repair
　　fix repair
　　fix up work on
　　float on the air be excited
　　floor department store
　　fly by pass
　　folks relatives
　　follow the example of ... follow suit
　　following the Civil War Post-Civil War
　　for a while at another time
　　for more space be well attended
　　for the third time this month again
　　forcing the mixture through tiny holes squeezing liquid through small holes
　　forecast expect
　　forget not think // quit
　　forget remember
　　form paperwork
　　forward deliver // send
　　four o'clock afternoon
　　four o'clock that afternoon
　　four weeks one month
　　free flexible
　　free of additives without additives
　　freeze be very uncomfortable
　　freeze cold
　　from ocean beds that dried up long ago in fossils on land
　　from time to time occasionally // now and then
　　front-row seats good seats
　　fun enjoy // enjoyable
　　function work
　　furnace heat system
　　furnace heating system