About Merging and exiting: 2/3 of the lane and the 300-metre rule: which statement is WRONG?
At a too-short merge lane you stop at the START of the lane, not halfway, and only pull away once you see a gap approaching in your left mirror.
You must merge as early as possible, as soon as there is a gap in the traffic, even if you are still only at the start of the merge lane.
Signal at approximately 300 metres before the start of the exit lane, using the green hectometre markers as an aid.
You must give way to through traffic; some drivers move left to give room, but that is not obligatory, so do not count on it.
Explanation
trap: 'can already' confused with 'must already'. Book p.148 - always use about 2/3 of the merge lane to get up to speed, even if you could merge earlier