There will 【be】 another bridge across the Yellow River,因为是there be 句型,How will the world【 be 】different in 50 years from now?will是情态动词,后面用动词原形,所以用be...
There will have (have改为be) another bridge across the Yellow River。 there be句型中的be不能换为have.但可以用exist, stand, lie, seem, happen 等。How will the world is (is改为be) different in 50 yea...