砂利をセメントで固める必要がある。

砂利: gravel, ballast, pebbles, small stones, shingle, gravelly, dirt
を: o, the, to, wo
セメント: cement
で: in, at, on, with, by, over, through
固める: harden, consolidate, fortify, freeze, to harden, to solidify, to strengthen, solidify, cement
必要: need, have, necessary, needed, required, must, want, essential, necessity, indispensable
が: is, there, but, ga, will, however
ある: a, is, an, be, there is, to be, locate