ゆっくり話せば、わかります。
If you speak slowly, they will understand.

高ければ、買いません。
If it is expensive, I won't buy it.

その道が安全なら(ば)、通ります。
If that road is safe, I'll take it.

いい条件なら(ば)、その会社につとめます。
If working conditions are good, I'll work at that company.

ゆっくり話さなければ、わかりません。
Unless you speak slowly, they will not understand.

高くなければ、かいます。
If it's not expensive, I'll buy it.

その道が安全でなければ、通りません。
Unless that road is safe, I won't take it.

いい条件でなければ、その会社につとめません。
Unless working conditions are good, I won't work for that company.