题目

单句改错。 找出每句中的一处错误并改正。 1. She often(A) helps(B) her mother doing(C) some(D) housework. 2. Do(A) you have(B) delicious something(C) to eat(D)? 3. First(A), put(B) the mayonnaise(C) in(D) a slice of bread. 4. Who(A) is(B) the girl(C) at(D) the bike? 5. Here(A) are(B) three slice(C) of chicken(D). 答案： 1. C. doing→ do/to do 2. C. delicious something→ something delicious 3. D. in→ on  4. D. at→ on  5. C. slice→ slices3．已知平面区域D={（x，y）|0≤x≤1，|y|≤1}，?（x，y）∈D，$\sqrt{{（x-\frac{1}{4}）}^{2}{+y}^{2}}$≥|x+$\frac{1}{4}$|的概率P=$\frac{1}{3}$．