The phrase "achieved only a" is correct and usable in written English.
It can be used when discussing the limited success or outcome of an effort or action.
Example: "Despite their hard work, they achieved only a fraction of their goals this year."
Alternatives: "attained merely a" or "reached just a".
With SUB-9 and SUB-12, the highest Recall values of 75.21 and 47.16 %, respectively, were achievable by MC_7 while P-DPA_M1 achieved only a Recall value of 56.23 % with SUB-9 and 43.59 % with SUB-12.
It feels like a real articulation of now, a style that couldn't have been achieved only a few years ago.
After a long festival run, Goodbye to Language achieved only a minimal theatrical release in the US, and went straight to DVD in the UK.
The same skepticism may also color the jury's view toward prosecutors, especially in the wake of the Bonds verdict, in which the prosecution achieved only a narrow victory.
But he had a terrible temper, a tendency to escalate rather than to defuse confrontations, and, by the time he was released, just before turning eighteen, he had achieved only a ninth-grade education.
The committee has nine Republicans, and even if they had been able to muster all their votes, they would have achieved only a tie in a roll call, under which the candidate loses.
In the west the Mahdist armies had achieved only an unstable occupation of Darfur.
As it was, the 8th Army, switched back from the west to the Adriatic coast, achieved only an indecisive breakthrough toward Rimini.
Negotiations this week between the major powers and Iran on its nuclear program achieved only an agreement to hold technical talks in March and then another meeting in April.
Even with a longer data collection period, Québec achieved only an 18% response rate.
