Pick out the most effective word/s from the given words to fill in the blanks to make the sentence meaningfully complete.
The boy did not know if he would be able to hold on _______ help arrived.
1
if
2
until
3
when
4
for
Pick out the most effective word/s from the given words to fill in the blanks to make the sentence meaningfully complete.
The boy did not know if he would be able to hold on _______ help arrived.