What are two examples of foreshadowing the author gives in the first half of the story "Ten Little Indians"?
First, just consider how vague the invitations were. Calling people to a remote island to "talk about old times" or to treat an unspecified "medical condition" should raise questions about the true purpose, especially when the group invited turns out to be both numerous and quite unknown to each other. But I think the first obvious example of foreshadowing occurs during the approach to the island. Vera comments that "there was something sinister" about it and she "shivered faintly." Big neon sign to readers - danger ahead!
The next example of foreshadowing, a bit more subtle, is the framed nursery rhyme that is hung in each of their rooms. The nursery rhyme counts up to ten little Indians - like the arrival of ten guests to the island - and then counts back down to one little Indians, which suggests a "departure" of the other nine. Combined with Vera's premonitory feelings and the vague information given to the visitors, this repetition of of the rhyme comes across as sinister, not casual.