After taking an aspirin, her headache……………(APPEAR)

1. After taking an aspirin, her headache………………….... (APPEAR)
2. My teacher usually …………………….me to take part in the ioe. (COURAGE)
3. We are waiting for the………………..…..of his plane. (ARRIVE)
4. He should read the…………………....well before using it. (INTRODUCE)
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