Answers: (Material for players past beginners is in blue.)
1.
Do you agree with your 1S response? What should you bid now?
Hint: Do you know what the final contract should be? Is it easier to take 10 tricks than 11?
You should agree with the 1S response; finding a major suit fit is our highest priority, and since 1S is forcing, there is no reason to jump. (A jump to 2S would show a much different hand. If you never jump shift as responder, you aren't missing much. Your forcing 1S response gives lots of room for partner to describe his hand that he wouldn't have over 2S.)
You have a spade fit, but your partner's 2S bid says partner is minimum (13-15 points.) You have enough for game but not enough for slam. You know where, you know how high. When you know, you go. Bid 4S.
Partner should have four spades but occasionally might have only three. Are you afraid that you might be in a bad spot? Where would you want to play on the following hand where partner eschewed his normal 1NT rebid because he feared his small heart doubleton?
With a 4-2 break, you'll easily make 4S and will take the same ten tricks in diamonds.
2.
Do you agree with your 1S response? What should you bid now?
Hint: Bids of suits shown previously generally aren't forcing. Your partner has about 16-18 points. Can you make a game?
Answer: You should agree with 1S. Our favorite contracts are the major suits when we can find a fit so bidding 1S (showing 6
or more points) is preferable to bidding 1NT to show weakness because a 1NT response denies a 4-card major.
Your partner has shown a medium hand for opener by jumping to the three level. That's about 16-18 points. (Some experts say 17-18.) Even if partner has 18 points, you do not have the required strength for game, so pass. (I usually say that you should have 26 points counting distribution for game; some will say 25, but you don't have that either.)
You might be saying, "If I have to take nine tricks anyway, why not try 3NT?" The problem is that playing in your eight-card fit usually takes a trick or two more than playing the same hand in notrump, so you could easily make 3S and have no play for 3NT. Against 3NT, the opponents will lead a club or a heart (since your side bid diamonds and spades) and will set up that suit and take tricks with small cards. In 3S, this won't happen as you can trump their small cards.
3.
Do you agree with your 1S response? What should you bid now?
Hint: When you bid 1S, you might have had six points. Partner, who could have bid 2S or 3S, decided to bid a game. Do you think his bid is a sign-off? What would motivate partner to bid game?
Answer: You should agree with the 1S response for the same reason as hand 1.
Your partner heard your 1S bid showing 6 or more points and yet is bidding game when he could have bid only 2S or 3S. Unless partner is insane, partner should have close to 20 points. You have 14 (counting a length point.) That is enough for a slam (we like to have 33 points to bid a slam.) Without any conventions, you should bid 6S.
If you and your partner play Blackwood, you can bid it to make sure you aren't missing two aces. If you are only missing one ace, you will still bid 6S. If you don't know what I'm talking about, and you bid 6S, take full credit.