In 2050, one of the biggest challenges of mankind is______.
A．to provide food for at least 9 billion people
B．to develop more cultivable land
C．to produce treble food on roughly the same area of land
D．to prevent droughts and floods

未分类题Which of the following is NOT true according to Paragraph 4?A．GM crops boost the output.B．GM crops are helpful to the wild habitat.C．GM crops are more resistant to various disasters.D．GM crops could vastly increase the productivity of farming.

未分类题Which of the following is NOT true according to Paragraph 2?A．Teaching ability is the most important factor in teachers' promotion.B．Other subjects have the same problems with economics.C．Morden universities pay more attention to research than teaching.D．Many teachers regard teaching as an obstacle in their work.

未分类题It can be inferred from the passage that______.A．today it' s still hard for a man to accept a successful wifeB．today the equality between couples is still importantC．women are more open-minded in the marriage bondsD．the ego of men is stronger than women' s

未分类题According to the passage, e-cigarettes______.A．supply smokers with nicotine more safelyB．help the fastest e-cigarettes-adopter gain sales 1 billion timesC．are mastered by all tobacco firms as a new technologyD．have lured smokers from the big tobacco brands to startups

未分类题It can be inferred from the passage that the Lancet is a journal on______.A．evolutionB．medicineC．economyD．sports