Ground to a halt on last 3 - would greatly appreciate help on:- 18 across Plant US coin in arid ground ?I?E???A;) have tried combinations of dime and arid and cent and arid) 27 down More substantial runs between lessons right for son in the end ???R?N?R and 20 down Far-flung island cut off in harsh winters ?T?Y?N Totally flummoxed!