No. The conjunction WHEN should be used instead of SINCE.
Grammatically, you could have the proper sentence "The swallows are flying to a warmer country since the weather has become cold." Either since or as or forcould be used, but any would mean because.
The swallows fly to warm countries since the weather is usually cold. The right conjunction should be because.
Monopoly
monopoly
MONOPOLY
Some will last around 4.5 billion years - until the sun becomes a red giant and effectively swallows the Earth.
When a comma is inserted into the middle of a sentence it becomes a compound sentence.
The word for seek in Latin is quaero, and opportunity is opoprtunitas. With the correct conjunction, the phrase becomes quaerebat opportunitatem.
Starting a sentence with a conjunction is generally considered informal or conversational in style, so it may not be appropriate in all writing contexts, such as academic or formal settings. However, it can be used effectively to create a more casual or engaging tone in creative writing or informal pieces.
Countries development becomes more faster
The sentence "He's surprised me" is fine. If the contraction is expanded, the sentence becomes "He has surprised me".
The central character becomes entangled in foreign affairs.
The verbs are 'to be' (conjugated as "is") and 'to become' (conjugated as "becomes").