put the verbs in brackets in the correct tense form: present perfect or present
perfect progressive.
1). my sister (to help) her mother since morning.
2). she already (to wash) the floor and (to dust) the furniture.
3). my father (to work) at the factory for fifteen years.
4). i (to wait) for a letter from my cousin for a month already, but (not yet to receive) it.
5). she already (to do) her homework for two hours, but she (not yet to do) half of it.
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