At the higher levels the time allowed is very limited. Having to attempt typing 6-7 word sentences in 8 seconds isn't realistic. Even getting answers correct doesn't necessarily increase time available.
It would be nice if you could say how difficult the Time Practice shall be.
In German to English I always have more than 1 minute, sometimes even 2 minutes after 20 mostly correct questions. In German by English I usually lose against the time.