Learn Swedish: Vad biodlaren gjorde var att öppna bikupan. - What the beekeeper did was open the beehive.

In Swedish pseudo-cleft sentences that focus on an action, you almost always keep the infinitive marker att after the linking verb. While English lets us drop the "to" (as in "what he did was open"), Swedish requires it: var att öppna (was to open).

Does the V2 (verb-second) rule apply here? Why isn't the verb right after Vad?

The V2 rule is still working! The entire clause Vad biodlaren gjorde acts as a single, giant subject. It takes up the whole first position in the sentence. The main verb of the sentence is var, which correctly sits right there in the second position.

How do the tenses work in this action-focused structure?

The first two verbs must match in tense. Because the beekeeper's action is in the past (gjorde), the linking verb must also be in the past (var). However, the actual action being highlighted is always placed in the infinitive (att öppna) regardless of when it happened.

How are the words biodlaren and bikupan built?

Both are compound words starting with bi (bee). En odlare is a grower or cultivator, making biodlaren the "bee-grower" (beekeeper). En kupa is a dome or hive, making bikupan the "bee-dome" (beehive).