未知题型 You will be informed about any subtle changes ________ .A at the first opportunityB for the first opportunityC in the first opportunityD on the first opportunity

未知题型 The better we understand ourselves, the easier it becomes to ________ our full potential.A live up toB reach up toC come up toD make up to

未知题型 The balloonists are waiting for ________ weather conditions before taking off.A considerableB invaluableC maximumD optimum