SỬA LỖI SAI. GIẢI THÍCH GIÚP MÌNH NHÉ. 21. The man died [as] a result [of falling] [asleep] while he [drives]. 22. I [haven't finished] the report [yet], but by the time you [return] I [will certainly comlete it]. 23. Caroline [has worn] hernew [yellow] dress only [once] since she [buys] it. 24. [We’ll be cycled] to [Hoa's village] [at] this time [next] Sunday. 25. What [will] you [do] [when] your friends [won't come]? 26. Some [was knocking] at [the door] when I [was doing] the [washing up]. 27. My friend [didn't drink] [any] beer since we [came] to live [here] . 28. We have [written] to [each other] [when] we [were] in primary school. 29. [After] breakfast, I'm [gone] to walk [to] school [with] my friends. 30. [Will] we [go to] the pop concert [this] weekend for [a change]?